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May 11, 2011

https://www.sciencedaily.com/releases/2011/05/110509114034.htm

The skinny on how shed skin reduces indoor air pollution

Flakes of skin that people shed at the rate of 500 million cells every day are not just a nuisance -- the source of dandruff, for instance, and a major contributor to house dust. They actually can be beneficial. A new study, published in the American Chemical Society's journal,

Charles Weschler and colleagues explain that humans shed their entire outer layer of skin every 2-4 weeks at the rate of 0.001 -- 0.003 ounces of skin flakes every hour. Those flakes contain skin oils, including cholesterol and "squalene," and are a major constituent of the dust that accumulates on tables and other surfaces in homes and offices. Past research suggested that squalene from passengers' skin had a role in reducing levels of ozone -- a pollutant that can irritate the eyes, nose and throat and worsen asthma symptoms -- from the air in airplane cabins."It is only within the last five years that we've grown to appreciate the central role that squalene (from human skin oil) plays in oxidation chemistry within indoor environments," the report notes. "More than half of the ozone removal measured in a simulated aircraft cabin was found to be a consequence of ozone reacting with exposed, skin, hair, and clothing of passengers."In the new study, the scientists set out to make the first extensive determinations of cholesterol and squalene in dust in homes and daycare centers and to figure out how these substances affect indoor air pollution. The scientists analyzed dust samples collected from 500 bedrooms of children aged 3-5 and the 151 daycare centers the children attended in the city of Odense, Denmark and its surroundings as part of the Danish Indoor Environment and Children's Health Study.Among their findings: "Squalene in settled dust … contributes, in a small way, to the indoor removal of ozone," reducing indoor ozone levels roughly 2 to 15 percent.The authors acknowledge funding from the Villum Foundation and FORMAS.

Ozone Holes

April 27, 2011

https://www.sciencedaily.com/releases/2011/04/110422090201.htm

Choosing the right electric vehicles batteries for the future

One of the most important decisions facing designers of plug-in electric or hybrid vehicles is related to battery choice. Now, researchers at the Norwegian University of Science and Technology (NTNU) have used a life cycle analysis to examine three vehicle battery types to determine which does the best job of powering the vehicle while causing the least amount of environmental impact during its production.

Their results, published in the latest edition of the scientific journal Environmental Science and Technology, show that on a per-storage basis, the nickel metal hydride (NiMH) battery had the most environmental impact, followed by the nickel cobalt manganese lithium-ion (NCM) and iron phosphate lithium-ion (LFP) batteries for all impacts considered, except ozone depletion potential. The researchers also found higher life cycle global warming emissions than have been previously reported.The researchers, Guillaume Majeau-Bettez, a PhD candidate in NTNU's Industrial Ecology Programme; Troy R. Hawkins, a researcher in the programme; and Anders Hammer Strømman, an associate professor in the programme, conducted a life cycle analysis of the three battery types and looked at 11 different types of environmental impacts from their production. These impacts included everything from greenhouse gas emissions to freshwater ecotoxicity, freshwater eutrophication and human toxicity.The researchers were surprised to find that except for ozone depletion potential, the NiMH battery performed significantly worse than the two Li-ion batteries for all impact categories. The researchers attributed this difference to the greater use phase efficiency of Li-ion relative to NiMH, and the fact that each kilogram of Li-ion battery is expected to store between 2 to 3 times more energy than the other battery types over the course of its lifetime."The NCM and LFP batteries contain at least an order of magnitude less nickel and virtually no rare earth metals," the researchers also observed. "Among Li-ion batteries, our analysis points to overall environmental benefits of LFP relative to NCM, which can be explained by a greater lifetime expectancy and the use of less environmentally intensive materials."For all three batteries, the energy requirements for their manufacture were a major cause of greenhouse gas emissions. One component of the analysis demonstrated the environmental significance of using polytetrafluoroethylene as dispersant/binder in the electrode paste. Its production was responsible for more than 97% of the ozone depletion potential of all three batteries, along with 14 -15% of the greenhouse gas production from the two Li-ion batteries, mostly due to the halogenated methane emissions. The final shipping and the production of the cell containers, module packaging, separator material, and electrolyte contribute relatively little to causing environmental damage, with collectively less than 10% of any impact category.The researchers also point out the importance of the choice of the functional unit for the life cycle analysis. While the production of NiMH causes the least greenhouse gas emissions impact per kilogram, its lower energy density makes it score worst both relative to its nominal energy capacity and the researchers' storage-based functional unit. Similarly, the greenhouse gas impacts of LFP and NCM production are roughly equal for a given mass or nominal energy capacity, but the greater life expectancy of LFP confers a net environmental advantage to this type of battery for a per-energy-delivered functional unit."A shift from NiMH to Li-ion may thus be viewed positively," the researchers concluded. "Though associated with important uncertainties, our results point to a higher than expected level of environmental impacts for the production and use of traction batteries. This inventory and life cycle analysis provide a basis for further benchmarking and focused development policies for the industry."

Ozone Holes

April 25, 2011

https://www.sciencedaily.com/releases/2011/04/110421141630.htm

Ozone hole linked to climate change all the way to the equator

In a study to be published in the April 21st issue of

This is the first time that ozone depletion, an upper atmospheric phenomenon confined to the polar regions, has been linked to climate change from the Pole to the equator."The ozone hole is not even mentioned in the summary for policymakers issued with the last IPCC report," noted Lorenzo M. Polvani, Professor of Applied Mathematics and of Earth & Environmental Sciences, Senior Research Scientist at the Lamont-Doherty Earth Observatory, and co-author of the paper. "We show in this study that it has large and far-reaching impacts. The ozone hole is a big player in the climate system!""It's really amazing that the ozone hole, located so high up in the atmosphere over Antarctica, can have an impact all the way to the tropics and affect rainfall there -- it's just like a domino effect," said Sarah Kang, Postdoctoral Research Scientist in Columbia Engineering's Department of Applied Physics and Applied Mathematics and lead author of the paper.The ozone hole is now widely believed to have been the dominant agent of atmospheric circulation changes in the Southern Hemisphere in the last half century. This means, according to Polvani and Kang, that international agreements about mitigating climate change cannot be confined to dealing with carbon alone -- ozone needs to be considered, too. "This could be a real game-changer," Polvani added.Located in Earth's stratosphere, just above the troposphere (which begins on Earth's surface), the ozone layer absorbs most of the Sun's harmful ultraviolet rays. Over the last half-century, widespread use of humanmade compounds, especially household and commercial aerosols containing chlorofluorocarbons (CFCs), has significantly and rapidly broken down the ozone layer, to a point where a hole in the Antarctic ozone layer was discovered in the mid 1980s. Thanks to the 1989 Montreal Protocol, now signed by 196 countries, global CFC production has been phased out. As a result, scientists have observed over the past decade that ozone depletion has largely halted and they now expect it to fully reverse, and the ozone hole to close by midcentury.But, as Polvani has said, "While the ozone hole has been considered as a solved problem, we're now finding it has caused a great deal of the climate change that's been observed." So, even though CFCs are no longer being added to the atmosphere, and the ozone layer will recover in the coming decades, the closing of the ozone hole will have a considerable impact on climate. This shows that through international treaties such as the Montreal Protocol, which has been called the single most successful international agreement to date, human beings are able to make changes to the climate system.Together with colleagues at the Canadian Centre for Climate Modelling and Analysis in Victoria, BC, Kang and Polvani used two different state-of-the-art climate models to show the ozone hole effect. They first calculated the atmospheric changes in the models produced by creating an ozone hole. They then compared these changes with the ones that have been observed in the last few decades: the close agreement between the models and the observations shows that ozone has likely been responsible for the observed changes in Southern Hemisphere.This important new finding was made possible by the international collaboration of the Columbia University scientists with Canadian colleagues. Model results pertaining to rainfall are notoriously difficult to calculate with climate models, and a single model is usually not sufficient to establish credible results. By joining hands and comparing results from two independent models, the scientists obtained solid results.Kang and Polvani plan next to study extreme precipitation events, which are associated with major floods, mudslides, etc. "We really want to know," said Kang, "if and how the closing of the ozone hole will affect these."This study was funded by a grant from the National Science Foundation to Columbia University.

Ozone Holes

April 18, 2011

https://www.sciencedaily.com/releases/2011/04/110418201736.htm

Electric cars need night time charging, evidence suggests

Researchers in America have shown that ozone -- a known pollutant at low levels in Earth's atmosphere, causing harmful effects on the respiratory system and sensitive plants -- can be reduced, on average, when electric vehicle charging is done at night time.

Ozone forms as hydrocarbons and nitrogen oxides, emitted into the air, react with sunlight. Two of the largest emitters of these pollutants are vehicles and electricity generating units (EGUs) with some of the most densely populated regions in the US still failing to meet the National Ambient Air Quality Standards after 30 years of regulation.Plug-in Hybrid Electric Vehicles (PHEVs) have risen in popularity over the past decade as a result of cheaper fuel costs (versus gasoline), increased efficiency, and positive impact on the environment due to lack of exhaust fumes.Charging PHEVs at night time is known to be more cost-effective and reliable; however, researchers publishing their work April 19, 2011 in IOP Publishing's journal PHEVs have the capability to run off battery power and gasoline. When PHEVs run off battery power they emit no pollutants from their exhaust, however, the EGU's -- which provide electricity to charge batteries -- do give off pollutants.As such, researchers at the Massachusetts Institute of Technology (MIT) and the University of Texas modelled the effect of replacing 20% of the vehicle miles travelled (VMT) by gasoline-run cars with PHEVs, using three different electric car charging scenarios to study the emission of pollutants, specifically ozone, in the state of Texas.There has been much debate regarding the best way to charge electric cars. The first scenario in this study was based on charging the car at off-peak times in the night. The second scenario involved charging to maximize battery life (charging just before use and only the amount of charge needed to complete the trip) and the third scenario involved charging the battery when it was a convenient time for the driver (typically just after vehicle use).The results of the study showed that the overall levels of pollution, resulting from EGU emissions associated with charging, were lower than the level of pollution resulting from the emissions associated with 20% of gasoline VMT.Although night time charging was shown to yield the highest amount of nitrogen oxides, this led to the least amount of ozone on average across all cities and hours modelled as there is no sunlight for the emissions to react with. By the time morning comes, the pollutants are dispersed and diluted by other processes such as the wind.The lead author Dr Tammy Thompson of MIT said: "The results in general show positive air quality results due to the use of PHEVs regardless of charging scenario with the nighttime charging scenario showing the best results on average by a small margin.""This further supports efforts to develop regulation to encourage nighttime charging; an example would be variable electricity pricing. As more of the fleet switches over to PHEVs and a larger demand is placed on the electricity grid, it will become more important that we design and implement policy that will encourage charging behaviours that are positive for both air quality and grid reliability."

Ozone Holes

April 8, 2011

https://www.sciencedaily.com/releases/2011/04/110406085634.htm

Record ozone loss over the North Pole

In the past few weeks, exceptional weather conditions have led to unprecedented ozone depletion over the Arctic. Ground and satellite observations by researchers at the Laboratoire Atmosphères, Milieux, Observations Spatiales (CNRS/UVSQ/UPMC) as well as French models show that ozone loss reached around 40% at the end of March. The phenomenon was caused by an extremely cold and persistent stratospheric winter, resulting in significant ozone destruction, which, unusually, continued into spring.

The ozone layer acts like a shield that protects life on Earth from harmful ultraviolet solar radiation. Ozone concentrations and total content have been continually monitored since the signing in 1987 of an international treaty, the Montreal Protocol, which regulates the production of halocarbons. These are chemical compounds that contain chlorine and bromine and cause the destruction of ozone in the stratosphere (the part of the atmosphere that extends from an altitude of around 10 to 50 km and where the concentration of ozone is at its highest). Since halocarbons remain in the atmosphere for tens of years, it will be several decades before their concentration falls back to its pre-1980 level.Destruction of stratospheric ozone takes place in the polar regions when temperatures drop below -80°C. At these temperatures, clouds form in the lower stratosphere. Chemical reactions inside them transform compounds derived from halocarbons -- which are harmless to ozone -- into active compounds. These processes lead to the rapid destruction of ozone when sunlight returns over the pole. In the Antarctic, the 'ozone hole' (which results from the destruction of over half the total ozone content in spring) is a recurring phenomenon due to the extremely low temperatures in the stratosphere every winter. In the Arctic, on the other hand, wintertime temperatures are warmer on average than at the South Pole, and weather conditions vary considerably from one year to the next. This explains why ozone depletion can be less significant there. This year, the record ozone loss observed was caused by extreme weather.Researchers at the Laboratoire atmosphère, milieux, observations spatiales (CNRS/UVSQ/UPMC) have access to a battery of measurement stations and infrared and UV-visible monitoring systems that monitor ozone on a daily basis all around the planet. These observations are part of the World Meteorological Organization and United Nations Environment Program's Global Ozone Observing System. This winter, observations as well as simulations carried out by these teams using the Reprobus model revealed an extremely significant drop in total ozone content over a wide area. The persistence and extent of this loss, which has lasted for several weeks and reached 40% at the end of March, are absolutely unprecedented. French and European teams are currently working in the field north of the Arctic Circle (Kiruna, Sweden) to take detailed observations of these exceptional conditions using instruments on board stratospheric balloons operated by CNES. And instruments at the Haute Provence observation station (sounding balloons and LIDAR system) will be used to detect the impact of this event on lower latitudes when springtime warming of the polar stratosphere pushes ozone-depleted air masses towards these regions.Without the Montreal Protocol, this year's ozone destruction would have been considerably worse. As long as chlorine and bromine concentrations in the stratosphere remain high, significant ozone depletion similar to that observed this year may happen again during exceptionally cold Arctic winters. According to the latest international report assessing the state of the ozone layer, ozone should recover its pre-1980 levels around 2045-60 over the South Pole, and probably one or two decades earlier over the North Pole.

Ozone Holes

April 5, 2011

https://www.sciencedaily.com/releases/2011/04/110405102202.htm

Record depletion of Arctic ozone layer causing increased UV radiation in Scandinavia

Over the past few days ozone-depleted air masses extended from the north pole to southern Scandinavia leading to higher than normal levels of ultraviolet (UV) radiation during sunny days in southern Finland. These air masses will move east over the next few days, covering parts of Russia and perhaps extend as far south as the Chinese/Russian border. Such excursions of ozone-depleted air may also occur over Central Europe and could reach as far south as the Mediterranean.

At an international press conference by the World Meteorological Organisation (WMO) in Vienna April 5, atmospheric researcher Dr. Markus Rex from Germany´s Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) pointed out that the current situation in the Arctic ozone layer is unparalleled."Such massive ozone loss has so far never occurred in the northern hemisphere, which is densely populated even at high latitudes," AWI researcher Markus Rex describes the situation. The ozone layer protects life on Earth's surface from harmful solar ultraviolet radiation. Because of the low inclination angle of the sun, exposure to ultraviolet radiation is not normally a public health concern at high northern latitudes. However, if ozone-depleted air masses drift further south over Central Europe, south Canada, the US, or over Central Asiatic Russia, for example, the surface intensity of UV radiation could lead to sunburn within minutes for sensitive persons, even in April.Whether and when this may occur can be forecasted reliably only in the short term. People should thus follow the UV forecasts of regional weather services. "If elevated levels of surface UV occur, they will last a few days and sun protection will be necessary on those days, especially for children," Rex recommends.The expected UV intensity during these short episodes will, however, remain in the range of typical exposure at the height of summer and below the values that occur during holiday trips to the tropics. Extreme caution is therefore unnecessary. "The concern is that people don't expect to get sunburn so rapidly early in the year and consequently don't take sun protection as seriously as in the middle of summer or while on vacation," states Rex. Any sunburn increases the risk of developing skin cancer later in life and this adverse effect is particularly pronounced in children."But provided that UV-protection is used it is safe and even healthy to exercise normal outdoor activities even during low ozone episodes. Particularly in countries high up in the north people tend to suffer from vitamin D deficit after the dark winter and Sun is a natural source of it," adds Dr. Esko Kyrö from Arctic Research Center at Finnish Meteorological Institute.The air masses with very low ozone concentrations will eventually disperse, as the sun warms the stratosphere and the winds change, as happens every year in spring. This will lead to somewhat lower ozone in spring and early summer this year, as the low ozone from the Arctic mixes with other stratospheric air throughout the northern hemisphere. This effect will be small, due to the large dilution of the ozone depleted air masses in background air.As noted some weeks ago, the Arctic stratosphere has been unusually cold this winter, resulting in a transformation of chlorine supplied by industrial compounds into other forms that aggressively remove ozone. Since then the ozone removal process gained additional momentum by the return of sunlight to the Arctic, which is needed for the chemical processes to occur. The current amount of ozone depletion above the Arctic is far beyond that recorded for any other spring, over the time when ozone has been measured by modern instrumentation. These findings are based on an international network of 30 ozone sounding stations in the Arctic and Subarctic that is coordinated by the Alfred Wegener Institute.This year's Arctic ozone depletion is caused by industrial CFCs and related compounds. Production of these chemicals was banned by the Montreal Protocol. Ozone loss was particularly large this winter due to unusually low temperature, which results in the presence of clouds in the polar stratosphere. Reactions on the surface of these clouds transform chlorine containing breakdown products of CFCs into compounds that aggressively remove ozone. Even though the Montreal Protocol has successfully banned the production of CFCs and related compounds, chlorine levels in the Arctic stratosphere are only about 5% below the prior peak level, due to the long atmospheric lifetime of CFCs (removal takes 50 to 100 years). The Arctic ozone layer will remain vulnerable to depletion for the next several decades, particularly following unusually cold winters. In contrast, temperatures within the Antarctic stratosphere are cold enough, each winter, to lead to widespread occurrence of stratospheric clouds that are part of the chain of events that causes the Antarctic ozone hole that occurs each spring.The stratosphere has been observed to cool, following the rise of greenhouse gases (GHGs), because heat that would otherwise reach the stratosphere is trapped below, warming the surface. The situation for the Polar Stratosphere is more complicated because of dynamical heating by waves generated in frontal systems. For several years, however, scientists have noted that the coldest winters in the Arctic stratosphere are getting colder, a development that enhances the ozone-destroying efficiency of the remaining CFCs and could be linked to rising levels of GHGs. "The current winter is a striking continuation of this tendency. Hence, we are not surprised by the fact that such massive ozone depletion has now occurred above the Arctic," says Rex. "Determining the role that GHG driven climate change might play for Arctic ozone loss is a great challenge and the subject of on-going research throughout the international atmospheric sciences community" states Ross Salawitch of the University of Maryland. The European Union contributes to financing this research in the RECONCILE project, a 3.5 million euro research programme in which 16 research institutions from eight European countries are working towards improved understanding of the Arctic ozone layer."On the basis of internationalagreements on protection of the ozone layer, the specifically the Montreal Protocol and its amendments, we expect, however, that ozone depletion due to CFCs will finally become passé towards the end of the century. This is an impressive success of international environmental policy under the umbrella of the United Nations. This success is only temporarily clouded by the record ozone loss above the Arctic this year," says Rex. For several decades, however, the fate of the Arctic ozone layer each spring will be closely linked to the evolution of temperatures in the polar stratosphere.

Ozone Holes

March 14, 2011

https://www.sciencedaily.com/releases/2011/03/110314100835.htm

Arctic on the verge of record ozone loss

Unusually low temperatures in the Arctic ozone layer have recently initiated massive ozone depletion. The Arctic appears to be heading for a record loss of this trace gas that protects Earth's surface against ultraviolet radiation from the sun. This result has been found by measurements carried out by an international network of over 30 ozone sounding stations spread all over the Arctic and Subarctic and coordinated by the Potsdam Research Unit of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) in Germany.

"Our measurements show that at the relevant altitudes about half of the ozone that was present above the Arctic has been destroyed over the past weeks," says AWI researcher Markus Rex, describing the current situation. "Since the conditions leading to this unusually rapid ozone depletion continue to prevail, we expect further depletion to occur." The changes observed at present may also have an impact outside the thinly populated Arctic. Air masses exposed to ozone loss above the Arctic tend to drift southwards later. Hence, due to reduced UV protection by the severely thinned ozone layer, episodes of high UV intensity may also occur in middle latitudes. "Special attention should thus be devoted to sufficient UV protection in spring this year," recommends Rex.Ozone is lost when breakdown products of anthropogenic chlorofluorocarbons (CFCs) are turned into aggressive, ozone destroying substances during exposure to extremely cold conditions. For several years now scientists have pointed to a connection between ozone loss and climate change, and particularly to the fact that in the Arctic stratosphere at about 20 km altitude, where the ozone layer is, the coldest winters seem to have been getting colder and leading to larger ozone losses. "The current winter is a continuation of this development, which may indeed be connected to global warming," atmosphere researcher Rex explains the connection that appears paradoxical only at first glance. "To put it in a simplified manner, increasing greenhouse gas concentrations retain Earth's thermal radiation at lower layers of the atmosphere, thus heating up these layers. Less of the heat radiation reaches the stratosphere, intensifying the cooling effect there." This cooling takes place in the ozone layer and can contribute to larger ozone depletion."However, the complicated details of the interactions between the ozone layer and climate change haven't been completely understood yet and are the subject of current research projects," states Rex. The European Union finances this work in the RECONCILE project, a research programme supported with 3.5 million euros in which 16 research institutions from eight European countries are working towards improved understanding of the Arctic ozone layer.In the long term the ozone layer will recover thanks to extensive environmental policy measures enacted for its protection. This winter's likely record-breaking ozone loss does not alter this expectation. "By virtue of the long-term effect of the Montreal Protocol, significant ozone destruction will no longer occur during the second half of this century," explains Rex. The Montreal Protocol is an international treaty adopted under the UN umbrella in 1987 to protect the ozone layer and for all practical purposes bans the production of ozone-depleting chlorofluorocarbons (CFCs) worldwide today. CFCs released during prior decades however, will not vanish from the atmosphere until many decades from now. Until that time the fate of the Arctic ozone layer essentially depends on the temperature in the stratosphere at an altitude of around 20 km and is thus linked to the development of earth's climate.

Ozone Holes

February 22, 2011

https://www.sciencedaily.com/releases/2011/02/110221120945.htm

Carbon sink at South Pole has grown recently, historical collections reveal

By studying collections of a marine bryozoan that date back to a famous 1901 expedition to the South Pole, researchers have found that those organisms were growing steadily up until 1990, when their growth more than doubled.

The data, reported in the February 22 issue of The bryozoan in question, known as "This is one of the few pieces of evidence that life in Antarctica has recently changed drastically," said David Barnes of the British Antarctic Survey. "These animals are taking more carbon dioxide out of circulation and locking it away on the seabed."The more rapid growth of He says the shift is most likely the result of ozone losses, which have led to an increase in wind speeds over the last decade. Those stronger winds are a boon to plankton, as they blow ice out of the way and drive greater circulation of surface waters."If we are right, this is a rare example of animals responding to one global phenomenon, the ozone hole, and affecting another, the greenhouse effect," Barnes said.The discovery would not have been possible without early marine collections assembled by the explorer Captain Robert Falcon Scott, a polar pioneer who led the British National Antarctic Expedition and British Antarctic Expeditions at the turn of the 20th century, along with specimens maintained by museums in the United Kingdom, United States, and New Zealand."Scott's most famous journey was to reach the South Pole, but a team lead by the Norwegian explorer [Roald] Amundsen beat them to it," Barnes said. "Scott's team died in 1912 on the journey back to his food depots, and so his exploits are often not associated with success. What is not so well known is that his voyages were first and foremost scientific ones, and the collections of material and information they made were impressive even by today's standards."The findings highlight the challenges of understanding the effects of large-scale processes such as the ozone hole or climate change. "This is not just because it is patchy in space and time, but also because of interactions between effects, as we found," Barnes said.It is not yet clear how big an impact the changes in "Nevertheless, we think that the combination of ice shelf losses and sea ice losses due to climate change and the effect of ozone loss-induced wind speeds offer some hope for much-needed carbon sequestration to the seabed in the Southern Ocean," Barnes said. "There are few other places in the world where global and regional changes could actually lead to more carbon being removed from the system."

Ozone Holes

February 21, 2011

https://www.sciencedaily.com/releases/2011/02/110220142805.htm

New assessment of black carbon and tropospheric ozone's role in climate change

Black carbon (BC) and tropospheric ozone (O

While our scientific understanding of how black carbon and tropospheric ozone affect climate and public health has significantly improved in recent years, the threat posed by these pollutants has catalysed a demand for knowledge and concrete action from governments, civil society, United Nations (UN) agencies and other stakeholders.The United Nations Environment Programme (UNEP) was requested to urgently provide science-based advice on actions to reduce the impact of these pollutants and the Integrated Assessment of Black Carbon and Tropospheric Ozone is the result. Its main findings are:Background information on the Integrated AssessmentThe assessment team examined policy responses, developing an outlook to 2070 illustrating the benefits of political decisions made today and the risks of delaying action for climate change, human health and crop yields over the next decades. Placing a premium on sound science and analysis, the Assessment was driven by four main policy-relevant questions:In order to answer these questions, the assessment team determined that new analyses were needed. The Assessment therefore relies on published literature as much as possible and on new simulations by two independent climate-chemistry-aerosol models: one developed at the NASA-Goddard Institute of Space Studies (NASA-GISS) and another developed by the Max Plank Institute in Hamburg and implemented at the European Commission's Joint Research Centre. The specific measures and emission estimates for use in developing this assessment were selected using the International Institute for Applied Systems Analysis' Greenhouse Gas and Air Pollution Interactions and Synergies (IIASA GAINS) model.The Summary of this assessment for decision makers will be presented at the 26th session of the Governing Council / Global Ministerial Environment Forum (GC/GMEF) of UNEP from 21-24 February 2011 in Nairobi, Kenya.

Ozone Holes

February 17, 2011

https://www.sciencedaily.com/releases/2011/02/110217003347.htm

Ozone layer’s future linked strongly to changes in climate, study finds

The ozone layer -- the thin atmospheric band high-up in the stratosphere that protects living things on Earth from the sun's harmful ultraviolet rays, not to be confused with damaging ozone pollution close to the ground -- faces potential new challenges even as it continues its recovery from earlier damage, according to a recently released international science assessment. The report, prepared by the Scientific Assessment Panel of the U.N. Montreal Protocol on Substances that Deplete the Ozone Layer, also presents stronger evidence that links changes in stratospheric ozone and Earth's climate.

The report finds that over the past decade, global ozone levels, and ozone levels in the Arctic and Antarctic regions are at a turnaround point -- no longer decreasing but not yet increasing. The abundances of ozone-depleting substances in the atmosphere are responding as expected to the controls of the Montreal Protocol, with many now declining in both the lower and upper atmosphere.By successfully controlling the emissions of ozone-depleting substances, the Montreal Protocol also has been beneficial for the climate, because many of these substances are heat trapping, or greenhouse, gases that are linked to Earth's warming."The Montreal Protocol has succeeded in protecting the ozone layer from much higher levels of depletion," said A.R. Ravishankara, director of NOAA's Chemical Sciences Division and co-chair of the Scientific Assessment Panel that produced the report. "But the ozone layer will increasingly be influenced by other factors related to the changing climate."For example, climate change alters the atmosphere's temperature and circulation patterns, which in turn affect the processes that deplete the ozone layer. One projected outcome of this relationship is that ozone in the Arctic, where the most severe changes in climate are being observed, is projected to be more sensitive to climate changes than ozone in the Antarctic, where climate change is relatively less of an influence on the ozone layer.Effects also work in reverse. Changes in the ozone layer have been linked to observed shifts in seasonal surface winds over the Southern Hemisphere, contributing to the Antarctic Peninsula warming and the high plateau cooling.The Antarctic ozone hole was discovered in 1985. Soon after, scientists established that the recurring springtime ozone hole was caused by human-made substances such as chlorofluorocarbons, or CFCs, used in refrigeration and halons used in fire extinguishers. The findings became a "science success story" as governments recognized the need for measures to reduce the production and consumption of a number of CFCs, halons and other ozone-depleting substances.The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted in 1987 and came into force in 1989. It was designed so that the schedules for phasing out ozone-depleting substances could be revised based on periodic scientific and technological assessments, be amended or adjusted to introduce other kinds of control measures, and to add new controlled substances to the list. The 2010 scientific assessment just released provides information needed by the Protocol's decision-makers during the coming few years as they consider possible further actions to protect the ozone layer.A return to pre-1980 levels of ozone is expected around mid-century in mid-latitude regions and the Arctic, with recovery in the Antarctic expected to follow later this century, according to the assessment.The ozone layer's continued protection depends on future adherence to the provisions of the Montreal Protocol, as well as potential new influences, such as possible unintended consequences of proposals to deliberately add compounds to the atmosphere to counteract warming due to heat-trapping gases."The Montreal Protocol is doing what it was designed to do and we are seeing less of the ozone-depleting substances covered by the agreement," said Ravishankara. "This has protected the ozone layer. But the atmosphere and climate are changing, so the ozone layer will not exactly retrace its steps."NOAA scientists and colleagues contributed findings that were critical to the assessment report. Namely, they led studies that determined the cause of the Antarctic ozone hole and elucidated the processes involved in ozone depletion in other regions of the globe. Teams have also tracked the state of the ozone layer and the abundances of ozone-depleting substances in the atmosphere, and modeled the past and projected future state of the ozone layer.The 2010 assessment was conducted under the auspices of the United Nations Environment Programme and the World Meteorological Organization. It involved more than 300 international scientists as authors and reviewers.The full report is posted on the UNEP website:

Ozone Holes

January 24, 2011

https://www.sciencedaily.com/releases/2011/01/110124074017.htm

What impact would sun dimming have on Earth's weather?

From the building of vast dams to conquering space, science has always taken human beings to the height of their ambition. Now, faced with a globally changing climate could Geoengineering provide an audacious solution? A special section of Atmospheric Science Letters investigates.

Solar radiation management projects, also known as sun dimming, seek to reduce the amount of sunlight hitting the Earth to counteract the effects of climate change. Global dimming can occur as a side-effect of fossil fuels or as a result of volcanic eruptions, but the consequences of deliberate sun dimming as a geoengineering tool are unknown.A new study by Dr Peter Braesicke, from the Centre for Atmospheric Science at Cambridge University, seeks to answer this question by focusing on the possible impacts of a dimming sun on atmospheric teleconnections.Teleconnections, important for the predictability of weather regimes, are the phenomenon of distant climate anomalies being related to each other at large distances, such as the link between sea-level pressure at Tahiti and Darwin, Australia, which defines the Southern Oscillation."It is important that we look for unintended consequences of any sun dimming schemes," said Braesicke. "We have to test our models continuously against observations to make sure that they are 'fit-for-purpose', and it's important that we should not only look at highly averaged 'global' quantities."Dr Braesicke's team believes that the link between tropical temperatures and extra-tropical circulation are well captured for the recent past and that the link changes when the sun is dimmed."This could have consequences for prevailing weather regimes," said Braesicke, "particularly for the El Nino/Southern Oscillation (ENSO) teleconnection. Our research allows us to assess how forced atmospheric variability, exemplified by the northern polar region, might change in a geoengineered world with a dimmed sun."A dimmed sun will change the temperature structure of the atmosphere with a cooling throughout the atmosphere. In the troposphere, temperatures drop because less solar radiation reaches the ground and therefore less can be converted into heat. In the stratosphere, less shortwave radiation is available for absorption by ozone and, therefore, heating rates in the stratosphere are lower."We have shown that important teleconnections are likely to change in such a geoengineered future, due to chemistry-climate interactions and in particular, due to changing stratospheric ozone," concluded Braesicke. "In our model, the forced variability of northern high latitude temperatures changes spatially, from a polecentred pattern to a pattern over the Pacific region when the solar irradiance is reduced. Future geoengineering studies need to consider the full evolution of the stratosphere, including its chemical behaviour."In an accompanying paper Ben Kravitz, from Rutgers University, reviews the new project to coordinate and compare experiments in aerosol geoengineering and evaluates the effects of stratospheric geoengineering with sulfate aerosols.Since the idea of geoengineering was thrust back into the scientific arena many have wondered whether it could reduce global warming as a mitigation measure. Kravitz's team argues that one of the most feasible methods is through stratospheric sulfate aerosols. While geoengineering projects are not yet favored by policy makers this method is inexpensive compared with other such projects and so may prove more attractive.However, stratospheric geoengineering with sulfate aerosols may have unintended consequences. Research indicates that stratospheric geoengineering could, by compensating for increased greenhouse gas concentrations, reduce summer monsoon rainfall in Asia and Africa, potentially threatening the food supply for billions of people."Some unanswered questions include whether a continuous stratospheric aerosol cloud would have the same effect as a transient one, such as that from a volcano, and to what extent regional changes in precipitation would be compensated by regional changes in evapotranspiration," said Kravitz.A consensus has yet to be reached on these, as well as other, important issues and to answer these questions the team propose a suite of standardised climate modeling experiments, as well as a coordinating framework for performing such experiments, known as the Geoengineering Model Intercomparison Project (GeoMIP).

Ozone Holes

January 10, 2011

https://www.sciencedaily.com/releases/2011/01/110106145434.htm

Atmosphere's self-cleaning capacity surprisingly stable

An international, NOAA-led research team took a significant step forward in understanding the atmosphere's ability to cleanse itself of air pollutants and some other gases, except carbon dioxide. The issue has been controversial for many years, with some studies suggesting the self-cleaning power of the atmosphere is fragile and sensitive to environmental changes, while others suggest greater stability. And what researchers are finding is that the atmosphere's self-cleaning capacity is rather stable.

New analysis recently published in the journal"The new hydroxyl measurements give researchers a broad view of the 'oxidizing' or self-cleaning capacity of the atmosphere," said Stephen Montzka, the study's lead author and a research chemist at the Global Monitoring Division of NOAA's Boulder, Colo., laboratory."Now we know that the atmosphere's ability to rid itself of many pollutants is generally well buffered or stable," said Montzka. "This fundamental property of the atmosphere was one we hadn't been able to confirm before."The new finding adds confidence to projections of future air pollutant loads. The hydroxyl radical, comprised of one oxygen atom and one hydrogen atom, is formed and broken down so quickly in the atmosphere that it has been extremely difficult to measure on global scales."In the daytime, hydroxyl's lifetime is about one second and is present at exceedingly low concentrations," said Montzka. "Once created, it doesn't take long to find something to react with."The radical is central to the chemistry of the atmosphere. It is involved in the formation and breakdown of surface-level ozone, a lung- and crop-damaging pollutant. It also reacts with and destroys the powerful greenhouse gas methane and air pollutants including hydrocarbons, carbon monoxide and sulfur dioxide. However, hydroxyl radicals do not remove carbon dioxide, nitrous oxide or chlorofluorocarbons.To estimate variability in global hydroxyl levels -- and thus the cleansing capacity of the atmosphere -- researchers turned to studying longer-lived chemicals that react with hydroxyl.The industrial chemical methyl chloroform, for example, is destroyed in the atmosphere primarily by hydroxyl radicals. By comparing levels of methyl chloroform emitted into the atmosphere with levels measured in the atmosphere, researchers can estimate the concentration of hydroxyl and how it varies from year to year.This technique produced estimates of hydroxyl that swung wildly in the 1980s and 1990s. Researchers struggled to understand whether the ups and downs were due to errors in emissions estimates for methyl chloroform, for example, or to real swings in hydroxyl levels. The swings would be of concern: Large fluctuations in hydroxyl radicals would mean the atmosphere's self-cleaning ability was very sensitive to human-caused or natural changes in the atmosphere.To complicate matters, when scientists tried to measure the concentration of hydroxyl radical levels compared to other gases, such as methane, they were seeing only small variations from year to year. The same small fluctuation was occurring when scientists ran the standard global chemistry models.An international agreement helped resolve the issue. In response to the Montreal Protocol -- the international agreement to phase out chemicals that are destroying the Earth's protective stratospheric ozone layer -- production of methyl chloroform all but stopped in the mid 1990s. As a result, emissions of this potent ozone-depleting gas dropped precipitously.Without the confounding effect of any appreciable methyl chloroform emissions, a more precise picture of hydroxyl variability emerged based on the observed decay of remaining methyl chloroform. The scientists studied hydroxyl radicals both by making measurements of methyl chloroform from NOAA's international cooperative air sampling program and also by modeling results with state-of-the-art models.The group's findings improve confidence in projecting the future of Earth's atmosphere."Say we wanted to know how much we'd need to reduce human-derived emissions of methane to cut its climate influence by half," Montzka said. "That would require an understanding of hydroxyl and its variability. Since the new results suggest that large hydroxyl radical changes are unlikely, such projections become more reliable."

Ozone Holes

December 8, 2010

https://www.sciencedaily.com/releases/2010/12/101207091811.htm

Using chaos to model geophysical phenomena

Geophysical phenomena such as the dynamics of the atmosphere and ocean circulation are typically modeled mathematically by tracking the motion of air or water particles. These mathematical models define velocity fields that, given (i) a position in three-dimensional space and (ii) a time instant, provide a speed and direction for a particle at that position and time instant.

"Geophysical phenomena are still not fully understood, especially in turbulent regimes," explains Gary Froyland at the School of Mathematics and Statistics and the Australian Research Council Centre of Excellence for Mathematics and Statistics of Complex Systems (MASCOS) at the University of New South Wales in Australia."Nevertheless, it is very important that scientists can quantify the 'transport' properties of these geophysical systems: Put very simply, how does a packet of air or water get from A to B, and how large are these packets? An example of one of these packets is the Antarctic polar vortex, a rotating mass of air in the stratosphere above Antarctica that traps chemicals such as ozone and chlorofluorocarbons (CFCs), exacerbating the effect of the CFCs on the ozone hole," Froyland says.In the American Institute of Physics' journal This technique is based on so-called "transfer operators," which represent a complete description of the ensemble evolution of the fluid. The transfer operator approach is very simple to implement, they say, requiring only singular vector computations of a matrix of transitions induced by the dynamics.When tested using European Centre for Medium Range Weather Forecasting (ECMWF) data, they found that their new methodology was significantly better than existing technologies for identifying the location and transport properties of the vortex.The transport operator methodology has myriad applications in atmospheric science and physical oceanography to discover the main transport pathways in the atmosphere and oceans, and to quantify the transport. "As atmosphere-ocean models continue to increase in resolution with improved computing power, the analysis and understanding of these models with techniques such as transfer operators must be undertaken beyond pure simulation," says Froyland.Their next application will be the Agulhas rings off the South African coast, because the rings are responsible for a significant amount of transport of warm water and salt between the Indian and Atlantic Oceans.

Ozone Holes

December 4, 2010

https://www.sciencedaily.com/releases/2010/12/101203141937.htm

Ozone hole affects upper-atmosphere temperature and circulation

Observations have shown differences in altitude and brightness between polar mesospheric clouds (clouds made of ice crystals in the upper mesosphere) in the Northern Hemisphere and those in the Southern Hemisphere.

Various mechanisms have been suggested to explain the differences; a new study shows that the ozone hole in the stratosphere above Antarctica could be playing a key role in the temperature and circulation patterns in the mesosphere (an atmospheric layer that begins 50 kilometers above Earth's surface, just above the stratosphere), leading to differences in polar mesospheric clouds.Using climate model simulations, Smith et al. show that the ozone hole causes a decrease in temperature in the lower stratosphere that persists into the summer. These temperature changes are accompanied by wind changes that modify the upward propagation of small-scale waves, which in turn alter the atmospheric circulation in the mesosphere in the Southern Hemisphere.The researchers find that the hemispheric asymmetry was small before 1980 but increased at about the same time as the onset of the ozone hole. A model run with no ozone loss showed no increases in the hemispheric asymmetry in mesospheric circulation and temperature, confirming that ozone loss is a likely cause of the hemispheric differences. They suggest that as the ozone hole recovers in upcoming decades, these trends in mesospheric temperature and circulation may change.

Ozone Holes

November 16, 2010

https://www.sciencedaily.com/releases/2010/11/101109214358.htm

Sunburnt whales: Three species show signs of sun damage to skin

Whales exhibit skin damage consistent with acute sunburn in humans, and it seems to be getting worse over time, reveals research published this week in

Scientists from the Zoological Society of London (ZSL), Queen Mary, University of London and CICIMAR, studied blue whales, fin whales and sperm whales in the Gulf of California to determine the effect of rising levels of ultraviolet radiation (UVR) on their health.For a number of years scientists have observed blisters on the skin of whales. Now, using high-quality photos to give accurate counts of the blisters and analysing areas of damage in skin samples, this research has found that the three species of whale exhibit skin damage that is commonly associated with acute sunburn in humans.Notably, the scientists also found that signs of sun damage were more severe in the paler-skinned blue whales, compared with the darker-skinned fin whales, and that in blue whales the symptoms of sunburn seem to be getting worse during the three years the study took place.The UV index for the Gulf of California fluctuates between high and extremely high throughout the year. Lead author, Laura Martinez-Levasseur from ZSL and Queen Mary, says, "Whales need to come to the surface to breathe air, to socialise and to feed their young, meaning that they are frequently exposed to the full force of the sun."The increase in skin damage seen in blue whales is a matter of concern, but at this stage it is not clear what is causing this increase. A likely candidate is rising UVR as a result of either ozone depletion, or a change in the level of cloud cover."Co-author Professor Edel O'Toole, from Queen Mary, says, "As we would expect to see in humans, the whale species that spent more 'time in the sun' suffered greater sun damage. We predict that whales will experience more severe sun damage if ultraviolet radiation continues to increase."The next phase of the research will look at the expression of genes involved in the production of skin pigmentation and DNA damage repair and try to gain a greater understanding of the consequences of sun damage in whales.Lead author Dr Karina Acevedo-Whitehouse, from ZSL says, "We have shown that exposure to strong sun is damaging to whales' skin. We now need to understand the knock-on effects and whether whales are able to respond quickly to increasing radiation by enhancing their natural sun-protection mechanisms."

Ozone Holes

November 13, 2010

https://www.sciencedaily.com/releases/2010/11/101108151330.htm

Discovery could reveal secrets of ancient Martian and terrestrial atmospheres

Chemists at UC San Diego have uncovered a new chemical reaction on tiny particulates in the atmosphere that could allow scientists to gain a glimpse from ancient rocks of what the atmospheres of the Earth and Mars were like hundreds of millions years ago.

Their discovery also provides a simple chemical explanation for the unusual carbonate inclusions found in a meteorite from Mars that was once thought by some scientists to be evidence of ancient Martian life."We never knew before how the atmosphere could be trapped in carbonate," said Mark Thiemens, dean of UC San Diego's Division of Physical Sciences who headed the team of scientists that detailed its discovery in the early online edition of the Robina Shaheen, a postdoctoral researcher in Thiemens' laboratory, discovered the chemical reaction and detailed its importance in the Earth's atmosphere after four years of painstaking experiments in which she found a higher than expected proportion of oxygen 17 isotopes in the carbonates found on dust grains, aerosols and dirt from various parts of the world.Martian meteorites, such as ALH84001, which was once thought to exhibit evidence of extraterrestrial life, have carbonates with similarly high oxygen 17 anomalies. Scientists have long attributed those anomalies to photochemical processes involving ozone and carbon dioxide in the thin atmosphere on Mars, which is bathed by intense ultraviolet radiation. But after finding similar anomalies on terrestrial carbonates formed in atmospheric aerosols, Shaheen surmised they might be the result of another chemical process more common to both planets.She analyzed in painstaking detail in the laboratory and in the Earth's atmosphere how ozone molecules interacted with oxygen-bearing mineral aerosols from dust, sea spray and other sources to form hydrogen peroxide and carbonates containing this same oxygen-isotope anomaly."What she found is that the tiny little layer on the outside of the grain is where this chemistry all happens," said Thiemens. "It's the ozone in the atmosphere mixing with water and carbon dioxide that drives a completely different kind of chemistry, one that's not in any of the models."While current models of atmospheric processes assume that the mixing of large volumes of gases drives the chemistry of the Earth's atmosphere, the UCSD chemists think their discovery may force a rethinking of this idea, particularly as the Earth's atmosphere becomes warmer and more dusty, providing more opportunities for this sort of chemistry to take place on aerosols."You can do chemistry on a grain that's a lot quicker and easier in many respects than is possible in other atmospheric processes," said Thiemens.Shaheen, who analyzed the carbonates in the Martian meteorite ALH84001 and found that they could have been formed on aerosols in ancient Martian atmosphere, said that NASA's Phoenix lander recently detected carbonates associated with particulates in the dusty atmosphere of Mars. "We think it might be this same mechanism that is operating," she added.Besides understanding current and future atmospheric processes on the Earth and Mars, the new discovery offers the possibility of mining information about the Earth's atmosphere, particularly its oxygen levels, from carbonates found in ancient rocks millions of years ago, far beyond the time period from which scientists can now obtain information about the ancient atmosphere from ice cores. The development of this new tool to probe ancient atmospheres could be the most significant aspect of the UCSD chemists' discovery."We've found a new way to measure the earth's atmosphere for time periods when we previously could not do it," said Thiemens. "What happened to ozone and oxygen levels 65 million years ago during the Cretaceous-Tertiary period when the dinosaurs and many other forms of life were killed in a mass extinction? Who died first? Did the food chain disappear before the dinosaurs? What happened 251 million years ago during the Permian-Triassic period, the most severe extinction of life on Earth, when 85 percent of life disappeared and no one knows why? There's no record of what happened in the atmosphere. But if you can find a record of what happened to oxygen levels, you can answer questions like that."Other researchers at UCSD involved in the study in Thiemens' laboratory were undergraduates Anna Abramian and John Horn. The research was partially supported by grants from National Aeronautics and Space Administration, the National Science Foundation and the UC San Diego Chancellor's Associates.

Ozone Holes

October 28, 2010

https://www.sciencedaily.com/releases/2010/10/101028143946.htm

Predicting smoggiest days: Experiments improve accuracy of ozone predictions in air-quality models

A research team led by NASA's Jet Propulsion Laboratory and the California Institute of Technology (Caltech), both in Pasadena, Calif., has fully characterized a key chemical reaction that affects the formation of pollutants in smoggy air in the world's urban areas. When applied to Los Angeles, the laboratory results suggest that, on the most polluted days and in the most polluted parts of L.A., current models are underestimating ozone levels by 5 to 10 percent.

The results -- published in the journal "This work demonstrates how important accurate laboratory measurements are to our understanding of the atmosphere," said JPL senior research scientist Stanley P. Sander, who led the JPL team's effort. "This is the first time this crucial chemical reaction has been studied by two teams using complementary methods that allow its details to be understood."The key reaction in question in this research is between nitrogen dioxide and the hydroxyl radical. In the presence of sunlight, these two compounds, along with volatile organic compounds, play important roles in the chemical reactions that form ozone, which at ground-level is an air pollutant harmful to plants and animals, including humans.Until about the last decade, scientists thought these two compounds only combined to form nitric acid, a fairly stable molecule with a long atmospheric life that slows ozone formation. Chemists suspected a second reaction might also occur, creating peroxynitrous acid, a less stable compound that falls apart quickly once created, releasing the hydroxyl radical and nitrogen dioxide to resume ozone creation. But until now they weren't sure how quickly these reactions occur and how much nitric acid they create relative to peroxynitrous acid. The JPL team measured this rate using a high-accuracy, JPL-built, advanced chemical reactor. The Caltech team then determined the ratio of the rates of the two separate processes.Theoretical calculations by chemistry professor Anne McCoy at Ohio State University, Columbus, contributed to understanding of the not-well-studied peroxynitrous acid molecule."This work was the synthesis of two very different and difficult experiments," added lead author and former Caltech graduate student Andrew Mollner with Aerospace Corporation, El Segundo, Calif. "While neither experiment in isolation provided definitive results, by combining the two data sets, the parameters needed for air quality models could be precisely determined."In the end, the researchers found the loss of hydroxyl radical and nitrogen dioxide is slower than previously thought-although the reactions are fast, fewer of the radicals are ending up as nitric acid than had been supposed, and more of them are ending up as peroxynitrous acid. "This means less of the hydroxyl radical and nitrogen dioxide go away, leading to proportionately more ozone, mostly in polluted areas," Okumura said.Just how much more? To try to get a handle on how their results might affect predictions of ozone levels, they turned to Robert Harley, professor of environmental engineering at the University of California, Berkeley, and William Carter, a research chemist at the University of California, Riverside-both experts in atmospheric modeling-to look at the ratio's impact on predictions of ozone concentrations in various parts of Los Angeles in the summer of 2010.The result: "In the most polluted areas of L.A.," said Okumura, "they calculated up to 10 percent more ozone production when they used the new rate for nitric acid formation."Okumura said this strong effect would only occur during the most polluted times of the year, not all year long. Still, he said, considering the significant health hazards ozone can have-recent research has reported that a 10 part-per-billion increase in ozone concentration may lead to a four percent increase in deaths from respiratory causes-any increase in expected ozone levels will be important to people who regulate emissions and evaluate health risks. The precision of these results reduces the uncertainty in the models-an important step in the ongoing effort to improve the accuracy of models used by policymakers.Okumura believes this work will cause other scientists to reevaluate recommendations made to modelers on the best parameters to use. For the team, however, the next step is to start looking at a wider range of atmospheric conditions where this reaction may also be important.Sander agrees. "The present work focused on atmospheric conditions related to urban smog-i.e., relatively warm temperatures and high atmospheric pressure," he said. "But the hydroxyl radical/nitrogen dioxide reaction is important at many other altitudes. Future work by the two groups will focus on the parts of the atmosphere affected by long-range transport of pollution by high-altitude winds [in Earth's middle and upper troposphere] and where ozone depletion from human-produced substances is important [the stratosphere]."The research was supported by grants from NASA, the California Air Resources Board, and the National Science Foundation, along with NASA and Department of Defense fellowships.

Ozone Holes

October 16, 2010

https://www.sciencedaily.com/releases/2010/10/101015090959.htm

Studies of radiative forcing components: Reducing uncertainty about climate change

Much is known about factors that have a warming effect on Earth's climate -- but only a limited amount is understood about factors that have a cooling effect. Researchers at the Center for International Climate and Environmental Research -- Oslo (CICERO) are working to fill the knowledge gap.

Gunnar Myhre has been working to reduce the level of uncertainty in projections from the Intergovernmental Panel on Climate Change (IPCC). With funding from the Research Council of Norway's NORKLIMA Programme, he and his research colleagues have studied as many radiative forcing components as possible simultaneously.Earth's temperature is determined by the difference between incoming solar energy and outgoing thermal radiation from Earth's surface and atmosphere that escapes into space. In its assessment reports, the IPCC estimates the energy balance using various radiative forcing components on Earth's climate.The IPCC's Fourth Assessment Report (2007) estimates the overall radiative forcing from anthropogenic carbon dioxide in the atmosphere to be 1.66 W/mThe IPCC was far less certain about the cooling effect of various anthropogenic radiative forcing components, particularly atmospheric aerosols (tiny, floating particulates and droplets). In 2007 the IPCC estimated that anthropogenic aerosols have a direct and indirect cooling effect, with a radiative forcing of -1.2 W/mIn recent years, scientists all around the world have taken part in a collective research effort to enhance knowledge about our planet's climate and to reduce uncertainty about the effects of various drivers of climate change. In the project Radiative forcing of climate change, Dr Gunnar Myhre and his colleagues have carried out climate modelling on a large scale with the aim of reducing the uncertainty associated with the degree of radiative forcing exerted by aerosols and ozone."Our objective has been to provide the IPCC with knowledge that enables them to produce better projections of climate change," says Dr Myhre.While greenhouse gases warm our climate, and aerosols in all probability act to cool it, factors such as ozone and changes in albedo (the reflectivity of different surfaces) can work both ways.For many years, human activities have sent vast amounts of aerosols into the atmosphere in the form of sulphate, black carbon and organic particulates. These anthropogenic aerosols are emitted in addition to natural aerosols such as sea salt, sulphate particles in volcanic ash, and sand from the Sahara.The Western countries have managed to lower their sulphate emissions dramatically. But China in particular is still emitting large amounts of both black carbon and sulphate, a situation causing tremendous health problems for millions of Chinese. So it is likely that within a few years, China will also focus on major reductions in emissions."When better sulphate abatement technology is available and emissions drop, it may lead to warming of the atmosphere," says Dr Myhre.Black carbon and sulphate are short-lived climate forcers, with atmospheric lifetimes of as little as a few weeks."More knowledge is needed about what will happen when atmospheric levels of black carbon and sulphate are reduced. They can either cool or warm the atmosphere -- but in all likelihood their primary effect is cooling," says Dr Myhre. In a 2009 article in the journal Researchers in the project "This makes it easier to understand the individual components, as well as how they affect each other and what uncertainties remain," explains Dr Myhre.Dr Myhre has worked particularly on aerosols and ozone. He has collaborated with other modelling groups and has been involved in developing a new model for the direct effect of anthropogenic aerosols -- a model that is now proving very useful in the IPCC's work."Based on our findings from the radiative forcing project, we have been able to reduce the uncertainty associated with the direct effects of aerosols considerably. Their cooling effect has proved to be less than previously thought. Biomass burning may have a significant effect on the radiation budget, but the net result of the warming and cooling effects is close to zero."Since the publication of the IPCC's Fourth Assessment Report, climate scientists have learned more about the various anthropogenic climate forcers, but still much remains to be done, according to Gunnar Myhre.

Ozone Holes

October 14, 2010

https://www.sciencedaily.com/releases/2010/10/101014121119.htm

Large gaps found in public understanding of climate change

Sixty-three percent of Americans believe that global warming is happening, but many do not understand why, according to a national study conducted by researchers at Yale University.

The report titled "Americans' Knowledge of Climate Change" found that only 57 percent know what the greenhouse effect is, only 45 percent of Americans understand that carbon dioxide traps heat from the Earth's surface, and just 50 percent understand that global warming is caused mostly by human activities. Large majorities incorrectly think that the hole in the ozone layer and aerosol spray cans cause global warming. Meanwhile, 75 percent of Americans have never heard of the related problems of ocean acidification or coral bleaching.However, many Americans do understand that emissions from cars and trucks and the burning of fossil fuels contribute to global warming and that a transition to renewable energy sources is an important solution.Americans also recognize their own limited understanding. Only 1 in 10 say that they are "very well-informed" about climate change, and 75 percent say they would like to know more about the issue. Likewise, 75 percent say that schools should teach children about climate change and 68 percent would welcome a national program to teach Americans more about the issue."This study demonstrates that Americans need to learn more about the causes, impacts and potential solutions to global warming," said study director Anthony Leiserowitz of Yale University. "But it also shows that Americans want to learn more about climate change in order to make up their minds and take action."The executive summary and full report are available online: The online survey was conducted by Knowledge Networks from June 24 to July 22, 2010, with 2,030 American adults 18 and older. The margin of sampling error is plus- or minus-2 percent, with 95 percent confidence.

Ozone Holes

October 6, 2010

https://www.sciencedaily.com/releases/2010/10/101005141516.htm

Antarctic sea ice increase not linked to ozone hole, new research shows

While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simulations have indicated that the ozone hole induces a large change in atmospheric circulation in austral summer and that this change in circulation could contribute to the changing Antarctic sea extent.

To learn more, M. Sigmond, of the Department of Physics at the University of Toronto, and J. C. Fyfe, of the Canadian Centre for Climate Modelling and Analysis, Environment Canada, used a climate model, forced by monthly varying observed stratospheric ozone changes from 1979 to 2005, to simulate the effects of stratospheric ozone depletion on Antarctic sea ice extent.Contrary to predictions of previous studies, their model finds that ozone depletion would lead to a year-round decrease in Antarctic sea ice extent rather than the increase that was observed. The results suggest that processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent.It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.The research appears in the journal

Ozone Holes

September 2, 2010

https://www.sciencedaily.com/releases/2010/09/100902141610.htm

Ozone depletion: Paving the way for identification of rogue CFC release

A new discovery by scientists at the Universities of East Anglia and Frankfurt could make it possible in future to identify the source of banned CFCs that are probably still being released into the atmosphere.

Using mass spectrometers, the researchers analysed air samples collected in the stratosphere by balloons belonging to the French space agency, the Centre National d'Etudes Spatiales (CNES). They discovered the largest chlorine isotope enrichment ever found in nature.CFCs were banned in most countries because of their depletion of the ozone layer. Due to their long lifetimes, their atmospheric concentrations are expected to decline only slowly. However, the observed decline is even slower than what scientists predicted. The likely reasons for this are the continued use of CFCs and emissions from old refrigerators, air conditioning units and waste disposal."We are particularly excited by this discovery because this is a totally new observation for atmospheric chlorine," said Johannes Laube, of the University of East Anglia's School of Environmental Sciences."Potentially, the technique we developed could enable us to identify remaining sources of CFCs in the atmosphere and to measure human contributions to naturally occurring ozone-depleting gases."The measurements were obtained from samples brought back by the stratospheric balloons, but the research group has now started experiments in a laboratory where they replicate the reactions in the stratosphere."We try to measure the isotope effect in our laboratory in simulated stratospheric conditions," says Dr Jan Kaiser, also of the School of Environmental Sciences. "We do need to do more method development work and gather additional information before we can identify the fingerprint of the isotope in this way, but this discovery opens the door to that possibility."

Ozone Holes

August 31, 2010

https://www.sciencedaily.com/releases/2010/08/100831094857.htm

Shifting ozone hole exposed South America to more ultraviolet light in 2009

The ozone layer, which protects humans, plants, and animals from potentially damaging ultraviolet (UV) light from the Sun, develops a hole above Antarctica in September that typically lasts until early December. However, in November 2009, that hole shifted its position, leaving the southern tip of South America exposed to UV light at levels much greater than normal.

To characterize this event and to evaluate satellite monitoring capabilities, de Laat et al. analyze satellite and ground-based measurements of ozone levels and the UV index (UVI). They find that the ozone column over southern South America was especially thin from 11 to 30 November 2009, and significantly higher UVI values were measured.Such abnormally low ozone levels sustained during a continuous period of three weeks had not been observed above southern South American at any time in the past 30 years, the researchers say. The high UVI values occurred over populated regions, meaning that humans had been exposed to increased levels of UV light. The scientists also note that the satellite-based measurements agreed well with the ground-based measurements, suggesting that satellite measurements can be valuable for monitoring ozone and UV radiation levels.Authors of the study include: A. T. J. de Laat, R. J. van der A, M. A. F. Allaart, and M. van Weele: Royal Netherlands Meteorological Institute, de Bilt, Netherlands; G. C. Benitez: Observatorio Central de Buenos Aires, Servicio Meteorológico Nacional, Buenos Aires, Argentina and PEPACG, Pontificia Universidad Católica Argentina, Buenos Aires, Argentina; C. Casiccia: Laboratorio de Monitoreo de Ozono y Radiación Ultravioleta, University of Magallanes, Magallanes, Chile; N. M. Paes Leme: Ozone Laboratory, National Institute for Space Research, São José dos Campos, Brazil; E. Quel, J. Salvador, and E. Wolfram: División Lidar, CEILAP, CITEFA, CONICET, Río Gallegos, Argentina.

Ozone Holes

August 12, 2010

https://www.sciencedaily.com/releases/2010/08/100811135043.htm

Texas petrochemical emissions down, but still underestimated, says study

A thick blanket of yellow haze hovering over Houston as a result of chemical pollution produced by manufacturing petroleum products may be getting a little bit thinner, according to a new study.

But the new findings -- which have implications for petrochemical-producing cities around the world -- come with a catch, says a team of scientists from the Cooperative Institute for Research in Environmental Sciences, or CIRES, a joint institute of the University of Colorado at Boulder and the National Oceanic and Atmospheric Administration.The problem is that industry still significantly underestimates the amounts of reactive chemicals being released into the air, according to airplane measurements made by the research team as part of the study. Inaccuracies in the reporting of emissions pose big challenges for the reduction and regulation of emissions coming from petrochemical plants. The emissions are important to monitor, because some chemicals released from the plants react to form ground-level ozone that can be harmful to human health and agricultural crops."Emissions may have decreased some, but there's still a long way to go," said study author Joost de Gouw, a CIRES atmospheric scientist. "And the emission inventories by industry were not any better in 2006 than they were in 2000."States that regularly suffer from ozone problems like Texas are required by the federal government to scientifically model what happens during air pollution episodes and develop plans for mitigation. For that to happen effectively, modelers need good inventories, says the research team."Initial inventories are not based on measurements. They're based on estimates," said de Gouw. "When you go back to verify those estimates, we find they're not very accurate."To check on those estimates, lead study author Rebecca Washenfelder of NOAA's Earth System Research Laboratory and CIRES, along with de Gouw, took to the plumes in an aircraft, the NOAA WP-3D, outfitted with an array of air quality measuring instruments. The plane flew through emissions over Houston as part of the second Texas Air Quality Study in 2006, sampling air for signs of ingredients of the chemical reaction that makes ozone, including nitrogen oxides and reactive hydrocarbons.Washenfelder, de Gouw and their study colleagues compared these measurements with data taken during similar flyovers from the first Texas Air Quality Study in 2000 and another flight in 2002. They then compared those measurements against emissions inventories for each year. In all cases, the industry-reported inventories -- which are supplied to the U.S. Environmental Protection Agency -- didn't agree with the measured amounts of pollutants.The conflicting data is likely a problem of estimation and general industry practice. "There are tens of thousands of valves and fittings installed throughout the plants in most cases with an assumed -- not measured -- leak rate for each," Washenfelder said.But industry is taking steps to lessen ozone-causing emissions, and repairs to petrochemical plants may have contributed to recent emission declines. Washenfelder and de Gouw found that the concentrations of ethene and propene -- which both contribute to ozone formation -- dropped by 52 percent and 48 percent respectively between 2000 and 2006.The two scientists see the study as a wake-up call for emissions monitoring."There are a lot of discussions with the petrochemical industry on how to measure these things instead of relying on estimates," said de Gouw. "I think the No. 1 issue here is awareness. As soon as industry is aware that there could be emissions problems down the road, they can figure out how to fix them at lower cost."The study been accepted for publication in the

Ozone Holes

August 5, 2010

https://www.sciencedaily.com/releases/2010/08/100804103648.htm

Travelling by car increases global temperatures more than travelling by plane, but only in the long term

Driving alone in a car increases global temperatures in the long run more than making the same long-distance journey by air according to a new study. However, in the short run traveling by air has a larger adverse climate impact because airplanes strongly affect short-lived warming processes at high altitudes.

The study, published in the journal In the long run the global temperature increase from a car trip will on average be higher than from a plane journey of the same distance. However, in the first years after the journey, air travel increases global temperatures four times more than car travel. Passenger trains and buses cause four to five times less impact than automobile travel for every kilometer a passenger travels. The findings prove robust despite the scientific uncertainties in understanding the earth's climate system."As planes fly at high altitudes, their impact on ozone and clouds is disproportionately high, though short lived. Although the exact magnitude is uncertain, the net effect is a strong, short-term, temperature increase," explains IIASA's Dr Jens Borken-Kleefeld, lead author of the study. "Car travel emits more carbon dioxide than air travel per passenger kilometer. As carbon dioxide remains in the atmosphere longer than the other gases, cars have a more harmful impact on climate change in the long term."The research also showed that when it comes to freight transport, moving goods by planes will increase global temperatures between 7 to 35 times more than moving the same goods the same distance in an average truck. Shipping on the contrary exerts 25 times less warming in the long run, and even cools on shorter time scales."Ships contribute to global warming through carbon dioxide, ozone and soot. Currently they also emit relatively large amounts of sulfur dioxide which forms sulfate particles in the atmosphere. Those particles cool the planet by reflecting solar radiation back into space," says co-author Dr Jan Fuglestvedt from CICERO. "In the first decades after a shipment, the cooling effect more than offsets the warming. And because of the large volumes of goods traded by ship, global trade actually counteracts some of the temperature increases caused by global passenger travel. However, in the long term all means of motorized transport add to global warming."The study concluded that as climate change acts at various time scales, it is important to have policies to reduce both the air pollutants that have strong, short-term impacts and the long-lived gases that lead to long-term warming. In addition, Dr Borken-Kleefeld argues: "A comprehensive strategy to tackle climate change caused by the transport sector is actually to minimize the demand for transport."

Ozone Holes

July 22, 2010

https://www.sciencedaily.com/releases/2010/07/100722181317.htm

Final instruments on NASA climate/weather satellite integrated

The last of five instruments slated to fly on the upcoming NPOESS Preparatory Project (NPP) climate and weather satellite have been successfully integrated, according to NASA officials. The polar-orbiting satellite is scheduled to launch in late 2011.

The NPP satellite was a pre-cursor mission to the National Polar-orbiting Operational Environmental Satellite System (NPOESS) that has recently been restructured. The last instrument, Cross-track Infrared Sounder (CrIS), is an advanced atmospheric sensor, built by ITT Corporation, Fort Wayne, Ind. Ball Aerospace & Technologies Corp., Boulder, Colo., built the NPP spacecraft and is performing the integration and checkout of the NPP satellite.The CrIS mechanical, electrical and performance testing was successfully completed and the NPP Satellite team is now working to finish the satellite Pre-Environmental Test baseline performance phase. The Environmental Test flow, which includes Dynamics, Electromagnetic Compatibility, and Thermal testing, is scheduled to begin this October.The five-instrument suite will collect and distribute remotely sensed land, ocean, and atmospheric data to the meteorological and global climate change communities. It will provide atmospheric and sea surface temperatures, humidity sounding, land and ocean biological productivity, cloud and aerosol properties and total/profile ozone measurements.Data produced by the CrIS instrument combined with data from the Advanced Technology Microwave Sounder, another NPP instrument, will provide global atmospheric temperature, moisture and pressure profiles from space.The other three instruments include: the Visible/Infrared Imager/Radiometer Suite, which will collect information about atmospheric clouds, the earth radiation budget, clear-air land/water surfaces, sea surface temperature, ocean color, and produces low light visible imagery; the Ozone Mapping and Profiler Suite, which will monitor ozone and continue the daily global data produced by the current ozone monitoring systems, but with higher fidelity and the Cloud and Earth Radiant Energy System that will measure the Earth's radiant energy balance and help researchers to develop improved weather forecasts and climate model predictions.The NPP mission is a NASA-managed project to provide continuity with NASA's Earth Observing System measurements and to provide risk reduction for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) managed by the NPOESS Integrated Program Office, a tri-agency program made up of NASA, NOAA and the U.S. Department of Defense. However in 2010, due to cost overruns and delays, a task force led by the President's Office of Science and Technology Policy recommended against continuing NPOESS.

Ozone Holes

July 22, 2010

https://www.sciencedaily.com/releases/2010/07/100722092227.htm

Key compound of ozone destruction detected; Scientists disprove doubts in ozone hole chemistry

For the first time, Karlsruhe Institute of Technology (KIT) scientists have successfully measured in the ozone layer the chlorine compound ClOOCl, which plays an important role in stratospheric ozone depletion. The doubts in the established models of polar ozone chemistry expressed by American researchers based on laboratory measurements are disproved by these new atmospheric observations. The established role played by chlorine compounds in atmospheric ozone chemistry is in fact confirmed by KIT's atmospheric measurements.

The ozone hole above the Antarctic and the destructive role of chlorofluorocarbons (CFC) and their decomposition products have become a synonym of both global environmental problems and their solution by concerted agreements worldwide. Scientific fundamental research into ozone chemistry of the atmosphere was the basis of international agreements, such as the Montreal Protocol of 1987, which has put limits on CFC production. The success of the political implementation of these scientific findings is reflected by the fact that the chlorine content of the atmosphere and, hence, the ozone destruction potential recently started to decrease slowly.For the first time, scientists from the Institute for Meteorology and Climate Research (IMK) have detected using atmospheric infrared measurements the important, but rather unstable chlorine monoxide dimer (ClOOCl) that plays a central role in stratospheric ozone destruction at the end of the Arctic winter. During the polar winter after sunrise, ClOOCl rapidly forms atomic chlorine which may catalytically decompose ozone. The extent of ClOOCl decay caused by the short-wave sunlight determines the extent of stratospheric polar ozone decomposition.However, understanding of the processes involved in ozone-destroying atmospheric chlorine chemistry was questioned by laboratory measurements of American scientists (F. Pope et al., "The atmosphere measurements made by KIT scientists above Northern Scandinavia with the balloon-borne infrared spectrometer MIPAS-B at heights of more than 20 kilometers clearly disprove the doubts of the American scientists and confirm the existing models of polar ozone chemistry," underlines Dr. Gerald Wetzel, member of the IMK staff. "Measurement and evaluation of balloon spectra require a very close cooperation of engineers and scientists, without which these important results would not have been possible."

Ozone Holes

July 22, 2010

https://www.sciencedaily.com/releases/2010/07/100721205553.htm

Smog might trigger cell death in the heart, study finds

An early study in rats provides the first direct indication that a major component of smog might trigger cell death in the heart, researchers reported at the American Heart Association's Basic Cardiovascular Sciences 2010 Scientific Sessions -- Technological and Conceptual Advances in Cardiovascular Disease.

The study found that exposure to ground-level ozone over several weeks increased the activity of a substance that triggers cell death in the heart.Ozone (O3) is a highly reactive gas made up of three oxygen molecules. In the upper atmosphere, it protects Earth from the sun's radiation. However, O3 becomes a major component of smog when it forms near the ground through reactions between sunlight, nitrogen oxides and hydrocarbons from fossil fuels and industrial processes."Several epidemiological studies have linked air pollution to the development of cardiovascular disease, but air pollution contains hundreds of chemicals and those studies were unable to separate out the effects of individual components," said Rajat Sethi, Ph.D., an assistant professor in the Department of Pharmaceutical Sciences at the Texas A&M Health Science Center Irma Lerma Rangel College of Pharmacy in Kingsville, Texas. "Our study looked for direct evidence of the role of ozone alone in cardiac dysfunction by creating a controlled environment."The researchers tested four groups of 10 rats living in clear plastic-glass boxes. The first two groups were exposed for eight hours a day to 0.8 parts per million (ppm) of O3 for either 28 or 56 consecutive days. The other two groups were exposed to 28 days or 56 days of clean, filtered air for eight hours per day. After the eight hours of testing, all the rats experienced 16 hours of clean air overnight.The study found that the hearts of the O3-exposed rats had increased levels of tumor necrosis factor-alpha (TNF α), an indication of inflammation compared to hearts of the control rats. Increased TNF α levels have been linked to a drop in levels of a heart-protective protein called Caveolin-1 (Cav1). Scientists believe Cav1 protects the heart by binding to a chemical called p38MAPK alpha (p38MAPK α), which is known to be a cell death signaling chemical, Sethi said.The researchers found that Cav1 levels decreased in the hearts of rats exposed to O3 compared to the hearts of control rats who breathed filtered air."We believe the decreased levels of Cav1 make more unbound p38MAPK α available for telling the heart cells to die. That link between Cav1 and O3 has never been shown in the heart," Sethi said.Co-authors are: Rama Surya Prakash Perepu, M.S.; Ajay Kumar, M.S.; Venkata Kashyap Yellepeddi, M.S.; Srinath Palakurthi, Ph.D.; Vishal Sethi, (high school intern); Carlos A Garcia, Ph.D.; and David Dostal, Ph.D.The study was in part funded by United States Environmental Protection Agency and the Texas A&M Health Science Center.

Ozone Holes

July 19, 2010

https://www.sciencedaily.com/releases/2010/07/100707180930.htm

'Business as usual' crop development won't satisfy future demand, research finds

Although global grain production must double by 2050 to address rising population and demand, new data from the University of Illinois suggests crop yields will suffer unless new approaches to adapt crop plants to climate change are adopted. Improved agronomic traits responsible for the remarkable increases in yield accomplished during the past 50 years have reached their ceiling for some of the world's most important crops.

"Global change is happening so quickly that its impact on agriculture is taking the world by surprise," said Don Ort, U of I professor of crop sciences and USDA/ARS scientist. "Until recently, we haven't understood the urgency of addressing global change in agriculture."The need for new technologies to conduct global change research on crops in an open-field environment is holding the commercial sector back from studying issues such as maximizing the elevated carbon dioxide advantage or studying the effects of ozone pollution on crops.However, U of I's Free Air Concentration Enrichment (FACE) research facility, SoyFACE, is allowing researchers to conduct novel studies using this technology capable of creating environments of the future in an open-field setting."If you want to study how global change affects crop production, you need to get out of the greenhouse," Ort said. "At SoyFACE, we can grow and study crops in an open-field environment where carbon dioxide and ozone levels can be raised to mimic future atmospheric conditions without disturbing other interactions."From an agricultural standpoint, one of the few positive aspects of global change has been the notion that elevated carbon dioxide in the atmosphere will stimulate photosynthesis and result in increased crop yields.But recent studies show that crops grown in open fields under elevated carbon dioxide levels resulted in only half the yield increase expected and half of what the United Nation's Intergovernmental Panel on Climate Change used in their model predictions regarding the world's food supply in 2050.There's no doubt that carbon dioxide levels are rising. At the beginning of the Industrial Revolution, atmospheric carbon dioxide levels were 260 parts per million (ppm). Today, those numbers have increased to 385 ppm. By 2050, carbon dioxide levels are expected to be 600 ppm."Elevated carbon dioxide is creating a global warming effect that in turn is driving other climate change factors such as precipitation patterns," Ort said. "By 2050, rainfall during the Midwest growing season is projected to drop 30 percent."U of I researchers are also studying how elevated ozone levels will affect crop yields.Soybean plants are being evaluated in elevated ozone at SoyFACE. New studies show that yields in the tri-state area of Indiana, Illinois and Iowa have been suppressed by 15 percent due to ozone pollution. Ort said if the same cultivars of soybean are used in 2050 that are being planted now, producers can expect to see an additional 20 percent drop in yield due to expected increases in ozone levels by the middle of the century."Ozone is a secondary pollutant caused by the interaction of sunlight with pollution clouds produced in industrialized areas and carried over rural areas by wind," Ort said. "For example, if pollution from Chicago blows out of the city into agricultural areas, it can interact with sunlight to produce ozone and cause plant yields to suffer."Because ozone is an unstable gas, its concentration levels vary greatly, Ort said. Thus, agricultural areas located near industrial areas will face the greatest challenges. Unfortunately, of the world's two top-growing areas for soybean -- the United States faces a much greater ozone challenge than Brazil."The SoyFACE experiment and historical data recorded over the past 10 years both indicate that for every additional one part per billion of ozone, soybean yields will decrease 1.5 bushels per acre," Ort said. "We are applying for funding to examine corn's sensitivity to ozone at SoyFACE, but a historical analysis indicates a significant sensitivity and yield loss."In addition to generating results about the response of crops to global change, SoyFACE has provided proof of concept that adaptation of crop plants to global change can be achieved in the field. Ort believes that this approach can and needs to be scaled to much larger sizes necessary for conventional selective breeding.Currently, only five FACE research facilities exist in the world. SoyFACE is the largest and most expansive in terms of number of global change factors under investigation. Researchers at SoyFACE are assisting in the development of additional FACE experiments in Brazil, India and Australia."FACE technology, coupled with revolutionary genomic tools, can markedly accelerate the breeding cycle," Ort said. "Once we discover the suites of genes that control the optimal response of plants growing in global change conditions, we can screen germplasm collections to narrow down hundreds of thousands of cultivars before testing the best ones in the field."Ort said top priorities of focus include tropical areas that are already food insecure and areas such as the U.S. Corn Belt that produce a large percentage of the world food supply."More research in these areas is critical," he said. "How top-producing areas fare with climate change will be very important in determining global food security for the future."This research was published in the

Ozone Holes

June 26, 2010

https://www.sciencedaily.com/releases/2010/06/100624122056.htm

Climate change complicates plant diseases of the future

Human-driven changes in the earth's atmospheric composition are likely to alter plant diseases of the future. Researchers predict carbon dioxide will reach levels double those of the preindustrial era by the year 2050, complicating agriculture's need to produce enough food for a rapidly growing population.

University of Illinois researchers are studying the impact of elevated carbon dioxide, elevated ozone and higher atmospheric temperatures on plant diseases that could challenge crops in these changing conditions.Darin Eastburn, U of I associate professor of crop sciences, evaluated the effects of elevated carbon dioxide and ozone on three economically important soybean diseases under natural field conditions at the soybean-free air-concentrating enrichment (SoyFACE) facility in Urbana.The diseases downy mildew, Septoria brown spot, and sudden death syndrome were observed from 2005 to 2007 using visual surveys and digital image analysis. While changes in atmospheric composition altered disease expression, the responses of the three pathosystems varied considerably, Eastburn said.Elevated carbon dioxide levels are more likely to have a direct effect on plant diseases through changes to the plant hosts rather than the plant pathogens."Plants growing in a high carbon dioxide environment tend to grow faster and larger, and they have denser canopies," Eastburn said. "These dense plant canopies favor the development of some diseases because the low light levels and reduced air circulation allow higher relative humidity levels to develop, and this promotes the growth and sporulation of many plant pathogens."At the same time, plants grown in high carbon dioxide environments also close their stomata, pores in the leaves that allow the plant to take in carbon dioxide and release oxygen, more often. Because plant pathogens often enter the plant through the stomata, the more frequent closing of the stomata may help prevent some pathogens from getting into the plant.In elevated ozone, plant growth is inhibited and results in shorter plants with less dense canopies. This can slow the growth and reproduction of certain pathogens. However, ozone also damages plant tissues that can help pathogens infect the plant more easily."Elevated levels of carbon dioxide and ozone can make a plant more susceptible to some diseases, but less susceptible to others," Eastburn said. "This is exactly what we've observed in our climate change experiments."U of I's SoyFACE was the first facility to expose plants to elevated ozone under completely open-air conditions within an agricultural field."The SoyFACE facility allowed us to evaluate the influence of natural variability of meteorological factors such as drought and temperature in conjunction with imposed atmospheric composition (elevated carbon dioxide and ozone) on naturally occurring soybean diseases across several growing seasons," Eastburn said.He believes rising temperatures and changes in rainfall patterns will also affect development of plant disease epidemics."In some cases, changes of only a few degrees have allowed plant diseases to become established earlier in the season, resulting in more severe disease epidemics," Eastburn said. "The ranges of some diseases are expanding as rising temperatures are allowing pathogens to overwinter in regions that were previously too cold for them."For example, warmer winters may allow kudzu to expand its range northward. Because kudzu is an alternate host for the soybean rust pathogen, one result of rising temperatures may be that soybean rust arrives in Illinois earlier in the soybean growing season, Eastburn said."Information derived from climate change studies will help us prepare for the changes ahead by knowing which diseases are most likely to become more problematic," he said. "Now is the time for plant pathologists, plant breeders, agronomists and horticulturalists to adapt disease management strategies to the changing environment."Eastburn's soybean research was recently published in This research was funded by the National Science Foundation, an SJU Sigma Xi grant, the Illinois Council on Food and Agricultural Research, the Soybean Disease Biotechnology Center, the Illinois Soybean Association, USDA Hatch funds, and the Office of Science, Department of Energy Grant.Eastburn will share his latest research on global climate change and the implications for future plant disease epidemics at the 2010 U of I Agronomy Day on Thursday, Aug. 19. For more information on Agronomy Day, go to

Ozone Holes

May 25, 2010

https://www.sciencedaily.com/releases/2010/05/100524173729.htm

Pollution dispersion research aids understanding of 2002 break-up of Antarctic ozone hole

The eruption of the volcano in Iceland has drawn attention to air flow patterns, as airlines lost millions of dollars and travelers remained stranded for days to weeks, as particles from the natural disaster traveled over Europe, forcing closures of major airports.

The flow of particles, although seemingly random, can be characterized more effectively, according to work done by Virginia Tech's Shane Ross of the engineering science and mechanics (ESM) department and his colleague Francois Lekien of École Polytechnique, Université Libre de Bruxelles, Belgium, who reported their findings in the publication Their research "will aid scientists and engineers in understanding and in controlling this type of global-scale phenomena, such as pollution dispersion in the atmosphere and the ocean, and large-scale transport of biological organisms, including airborne plant pathogens and respiratory disease agents," said Ishwar Puri, head of the ESM department at Virginia Tech.For example, the current British Petroleum oil spill in the Gulf of Mexico, might be modeled using Ross and Lekien's findings to provide greater insight into how the particles might be dragged into the Gulf of Mexico's Loop Current.In explaining how they conducted their research on the flow of particles, Ross and Lekien said they employed existing scientific principles of Lagrangian coherent structures, which reveals the separation of the atmosphere into dynamically distinct regions, to investigate the shapes of geophysical flow patterns.They used the 2002 discovery of the Antarctic Hole in their work because they viewed it as a "prototype atmospheric event" allowing for their studies on topological divisions on the mixing and transport of atmospheric tracers.As the media worldwide broadly publicized the finding of the Antarctic hole, it became the focus of the atmospheric science community. As Ross described the event, when the ozone hole split in two, allowing one of its fragments or regions to reassert its position over the Antarctic Pole while the other one spread into the mid-latitude regions, it implied "a sudden stratospheric warming."This type of global warming occurs in roughly half of all winters in the Arctic. The scientific explanation, Ross said, is "they are produced by the dynamic momentum force resulting from the breaking and dissipation of planetary-scale Rossby waves in the stratosphere."This phenomenon had never been observed in the Antarctic prior to 2002, according to reliable records that go back some 50 years. Consequently, Ross and Lekien labeled it a "prototype" of rare atmospheric events.Reviewing data from the event, they were able to determine that an isolated "blob of air" was slowly rotating over Antarctica. Lagrangian coherent structures, some which repel nearby air and some that attract it, formed inside the vortex. The vortex pinched off, sending the northwestern part of the ozone hole off into the mid latitude range while the southwestern portion returned to its regular position over the South Pole.Consequently, they write, when there is more than one vortex flow on a sphere, such as the planet Earth, "complicated spatial structures can arise and evolve, such as the polar vortex split." They were able to model this event, capturing some of its dynamic features."This model is very relevant both in atmospheric and oceanographic settings when one considers large-scale phenomena where the spatial geometry of the Earth's surface becomes important. The full spherical geometry, as opposed to tangent plane approximations, is particularly important when considering global streamline patterns generated by a given vorticity distribution…These patterns, in turn, provide the dynamical templates by which one can begin to understand the chaotic advection of particles in a vortex-dominated flow."

Ozone Holes

May 18, 2010

https://www.sciencedaily.com/releases/2010/05/100517172302.htm

Invasive kudzu is major factor in surface ozone pollution, study shows

Kudzu, an invasive vine that is spreading across the southeastern United States and northward, is a major contributor to large-scale increases of the pollutant surface ozone, according to a study published the week of May 17 in the journal

Kudzu, a leafy vine native to Japan and southeastern China, produces the chemicals isoprene and nitric oxide, which, when combined with nitrogen in the air, form ozone, an air pollutant that causes significant health problems for humans. Ozone also hinders the growth of many kinds of plants, including crop vegetation."We found that this chemical reaction caused by kudzu leads to about a 50 percent increase in the number of days each year in which ozone levels exceed what the Environmental Protection Agency deems as unhealthy," said study co-author Manuel Lerdau, a University of Virginia professor of environmental sciences and biology. "This increase in ozone completely overcomes the reductions in ozone realized from automobile pollution control legislation."Lerdau and his former graduate student, lead author Jonathan Hickman -- now a postdoctoral fellow at Columbia University -- used field studies at three sites in Georgia to determine the gas production of kudzu. They then worked with Shiliang Wu and Loretta Mickley, atmospheric scientists at Harvard University, who used atmospheric chemistry computer models to evaluate the potential 50-year effect of kudzu invasion on regional air quality."Essentially what we found is that this biological invasion has the capacity to degrade air quality, and in all likelihood over time lead to increases in air pollution, increases in health problems caused by that air pollution, and decreases in agricultural productivity," Lerdau said."This is yet another compelling reason to begin seriously combating this biological invasion. What was once considered a nuisance, and primarily of concern to ecologists and farmers, is now proving to be a potentially serious health threat."Ozone acts as an irritant to the eyes, nose and throat, and can damage the lungs, sometimes causing asthma or worsening asthma symptoms. It also is a mutagen and can cause lung cancer.Ozone, while essential to the health of the Earth in the upper atmosphere where it shields the surface from excess ultraviolet radiation, is hazardous to human health when it forms at the earth's surface. This occurs most often in the summertime as plants grow and produce chemicals that react with the air.Introduced to the United States in the late 19th century, kudzu, with its unique nitrogen-fixing physiology, allows a rapid, nearly uninhibited rate of growth, about three times the rate of trees and other vegetation. The vine was cultivated more extensively in the 1920s and 1930s as a control for soil erosion and rapidly became known as "the vine that ate the South."In recent, milder winters, Kudzu has expanded its range northward into Pennsylvania and New York."What was once a Southern problem is now becoming an East Coast issue," Lerdau said.Various strategies are used for controlling and eradicating kudzu, including livestock grazing, burning, mowing and herbicides.

Ozone Holes

May 3, 2010

https://www.sciencedaily.com/releases/2010/05/100503010957.htm

NASA study sheds light on ozone hole chemistry

A new NASA study of Earth's polar ozone layer reinforces scientists' understanding of how human-produced chlorine chemicals involved in the destruction of ozone interact with each other.

A team of scientists led by Michelle Santee of NASA's Jet Propulsion Laboratory, Pasadena, Calif., examined how nighttime temperatures affect chlorine monoxide, a key chemical involved in ozone destruction. Combining NASA satellite measurements with a state-of-the-art chemical model, they found this relationship to be more consistent with recent laboratory work than with some older laboratory and field observational data. This verification is important, because scientists have not been able to conduct appropriate laboratory experiments relevant to understanding how polar chlorine monoxide behaves at night at the lowest temperatures of the stratosphere, Earth's second lowest atmospheric layer.Santee and her team published their findings this month in the Proceedings of the National Academy of Sciences. The data came from the Microwave Limb Sounder instrument on NASA's Aura satellite."Our comprehensive study uses multiple years of Arctic and Antarctic satellite observations to quantify the nighttime balance of ozone-destroying chlorine chemical compounds," said Santee. "By gaining a better knowledge of this balance, scientists will be able to make more accurate predictions of polar ozone loss, especially in twilight and in the Arctic, where conditions are often only marginally favorable for ozone destruction."At night, chlorine monoxide molecules combine to form chlorine peroxide, and the balance between these two chemicals is highly temperature-sensitive. Studying this balance quantitatively is challenging. Previous studies in the laboratory and using aircraft and satellites had found significantly different degrees of balance. The Microwave Limb Sounder's very large number of measurements has quantified this balance far better than before.The new research contributes to scientific understanding of the phenomenon more commonly known as the "ozone hole." Each year in late winter and early spring in the southern hemisphere, chlorine and bromine from human-produced compounds cause the nearly total destruction of ozone in Earth's stratosphere in a layer about 20 kilometers (12 miles) above Antarctica. These source gases that are responsible for the greatest destruction of the ozone layer are now declining in response to the 1985 Montreal Protocol and its amendments.Since its launch in 2004, the Microwave Limb Sounder has monitored most of the polar regions of both hemispheres daily, compiling tens of thousands of measurements of nighttime chlorine monoxide levels, along with various other chemicals, including ozone. These data are allowing scientists to test their understanding of chlorine-related chemistry on an unprecedented scale.For more information on the Microwave Limb Sounder, see

Ozone Holes

April 27, 2010

https://www.sciencedaily.com/releases/2010/04/100422153810.htm

Ozone and traffic pollution increase asthma-related hospitalizations in children

Both ozone and primary pollutants from traffic substantially increase asthma-related emergency department visits in children, especially during the warm season, according to researchers from the Department of Environmental Health at the Rollins School of Public Health at Emory University in Atlanta.

The findings were published on the American Thoracic Society's Web site ahead of the print edition of the Asthma exacerbations are known to be triggered by air pollutants, but researchers are still trying to disentangle which specific pollutants are to blame, and the extent to which they increase pediatric emergency department visits for asthma."Characterizing the associations between ambient air pollutants and pediatric asthma exacerbations, particularly with respect to the chemical composition of particulate matter, can help us better understand the impact of these different components and can help to inform public health policy decisions," said lead author Matthew J. Strickland, Ph.D., M.P.H., assistant professor of environmental health.The researchers obtained data on metropolitan Atlanta emergency department visits for asthma exacerbations in children between five and 17 years of age between 1993 and 2004 and used data on ambient pollutant collected as part of the Study of Particles and Health in Atlanta (SOPHIA). They then analyzed the more than 90,000 asthma-related pediatric emergency department visits with respect to the ambient levels of 11 different pollutants. The availability of daily monitoring data on particulate matter components allowed them to develop a detailed picture of pollutant concentrations and subsequent effects on emergency department visits for pediatric asthma exacerbations.Ozone was strongly associated with an increase in pediatric asthma exacerbations during the summer, and there was evidence of a dose-response relationship beginning with concentrations as low as 30 parts per billion.Importantly, the current EPA 8-hour ozone standard is based on the three-year average of the fourth-highest measured concentration at any monitor, which must not exceed 75 ppb. Ozone concentrations in many urban areas throughout the U.S., including metropolitan Atlanta, routinely exceed the EPA standard.Several markers of pollution from combustion engines -- i.e., pollutants emitted from the tailpipes of cars and trucks -- were also associated with pediatric emergency department visits for asthma exacerbations during the warm season. When they analyzed the effects of multiple pollutants together, the researchers found evidence that ozone and primary pollutants from traffic sources independently affected pediatric asthma exacerbations.The researchers offered several possible explanations for why the pollution effects appeared stronger in the warm season, noting that "during the summer children are more likely to play outside" and postulating that there may be an "unidentified synergism between the pollutant and a meteorological or physical factor." Overall rates of emergency department visits for pediatric asthma increased by 60 percent in the cold season, probably because of the important role that respiratory infections have in triggering exacerbations."In this study we observed evidence that ambient concentrations of ozone and primary pollutants from traffic sources independently contributed to the burden of emergency department visits for pediatric asthma," wrote Dr. Strickland. "Further, the associations were present at relatively low ambient concentrations, reinforcing the need for continued evaluation of the EPA's National Ambient Air Quality Standards to ensure that the standards are sufficient to protect susceptible individuals."

Ozone Holes

April 21, 2010

https://www.sciencedaily.com/releases/2010/04/100421121503.htm

Animal feed, not automobiles, makes the San Joaquin Valley a smog hotspot

A new study identifies cattle feed as a possible culprit in the long-standing mystery of why California's San Joaquin Valley -- a moderately-populated agricultural region -- has higher levels of ozone (one of the main ingredients in smog) than many densely-populated cities. The report, which explains how fermented cattle feed works with automotive exhausts in forming ozone, is in ACS'

Michael Kleeman and colleagues note that high ozone levels in the San Joaquin Valley, which produces 10 percent of America's food, have puzzled scientists for years. Motor vehicles are the major source of smog elsewhere, but the Valley has fewer motor vehicles compared to big urban areas with similar levels of ozone. Suspicion thus fell on farming activities, and the new study investigated the role of fermented livestock feed.The paper documents emissions of reactive organic gases, which react with combustion emissions and sunlight to form smog, from seven different animal feeds. It shows how fermented feed like silage appears to be the largest man-made source of these organic gases that contribute to ozone formation in the Valley even more than automobiles. The until-now-unrecognized animal-feed factor may account for the failure of traditional vehicle smog control regulations in the Valley, they note.

Ozone Holes

April 14, 2010

https://www.sciencedaily.com/releases/2010/04/100409134731.htm

Measuring global water vapor and formaldehyde

Atmospheric water vapour (H

Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapour. In contrast to other important greenhouse gases like carbon dioxide (COGlobal monitoring of HFormaldehyde (HCHO) is one of the most abundant hydrocarbons in the atmosphere and is an important indicator of so-called non-methane volatile organic compound (NMVOC) emissions and photochemical activity. As such, it is an indicator of the presence of volatile organic compounds in the atmosphere, which in turn play an important role in the formation of toxic ozone close to the surface and also have an important influence on climate through the formation of large aerosol particles. HCHO is a primary emission product from biomass burning and fossil fuel combustion, but its principle source in the atmosphere is the photochemical oxidation of methane and non-methane hydrocarbons. Metop-A measurements of HCHO can be used to constrain NMVOC emissions in current state-of-the-art chemical transport models used in the forecasting and analysis of pollution events and also in modelling climate change.Operational GOME-2 HGOME-2 H

Ozone Holes

April 13, 2010

https://www.sciencedaily.com/releases/2010/04/100412111631.htm

Exposure to nitrogen dioxide lowers in vitro fertilization success

Exposure to an increased level of air pollutants, especially nitrogen dioxide, has been associated with lower likelihoods of successful pregnancy among women undergoing in vitro fertilization, according to a team of fertility researchers.

The team examined the outcomes of the first pregnancy attempt of 7,403 women undergoing IVF at Penn State Milton S. Hershey Medical Center, Hershey, Pa.; Shady Grove Fertility, Rockville, Md.; and Columbia University College of Physicians and Surgeons, New York, N.Y. They conducted their observations over a seven-year period from 2000 to 2007."Numerous studies have consistently shown a relationship between air pollution and human health, ranging from mortality, cardiovascular disease and other chronic conditions," said Duanping Liao, Ph.D., professor of epidemiology and vice chair department of public health sciences, Penn State College of Medicine. "In the process of searching for the mechanisms responsible for the above associations, we, and others, have reported significant links between air pollution and inflammation and increased blood clotting. These intermediate factors are also associated with reproductive health."The IVF population was chosen, as it is a well-controlled and timed process to investigate the association of air pollution and human reproductive effects.Burning of fossil fuels and diesel engine combustion produces nitrogen dioxide and fine particles. Researchers looked at those pollutants along with ozone, the gas involved in smog formation. While the effects of declining air quality on IVF success are variable and pollutant-dependent, elevated exposures to nitrogen dioxide and fine particles were consistently associated with lower success rates of pregnancy.Researchers looked at the effects of pollution particles both individually -- single pollutant model, and with other particles -- multi-pollutant model. For the single pollutant model, exposure to ozone appeared to have a positive association with a successful birth if the exposure was before the embryo culture or embryo transfer. Researchers theorize that higher ozone levels indicate lower nitrogen dioxide levels, which would show better pregnancy outcomes. In addition, for the multi-pollutant model, the "positive" effects of ozone were diminished with the addition of nitrogen dioxide. In contrast, after adjusting for ozone, higher nitrogen dioxide exposures consistently associated with the lower success rate, regardless of which indictor was used -- positive pregnancy test, clinically confirmed intrauterine pregnancy or live birth.These findings may be useful in studying the adverse effects of air pollution on human reproduction in general."Since IVF is a well controlled and highly timed process, we have a much better handle on the assessment of the time of exposures to elevated air pollutants in relationship to fertilization, pregnancy, and delivery," Liao said. "Therefore, the IVF population coupled with detailed assessment of air pollution exposures may provide us an ideal situation to investigate the potential health effects of air quality on human reproduction."Air pollutant concentration data for the study period came from the U.S. Environmental Protection Agency. The researchers calculated daily pollution concentrations for each patient during the entire in vitro cycle and pregnancy. They calculated varying periods of air quality exposure for average daily concentrations at the patient's home during four stages of IVF and at the IVF clinic during fertilization and embryo transfer.The researchers published their results in Other researchers on this study were Xian Li, Ph.D., postdoctoral fellow, public health sciences, and Richard S. Legro, M.D., and William C. Dodson, M.D., professors, obstetrics and gynecology, all at Penn State College of Medicine; Mark V. Sauer, M.D., Columba University College of Physicians and Surgeons, department of obstetrics and gynecology; Gilbert L. Mottla, M.D., and Kevin S. Richter, Ph.D., Shady Grove Fertility.

Ozone Holes

April 9, 2010

https://www.sciencedaily.com/releases/2010/04/100408150742.htm

NASA's Global Hawk completes first science flight

NASA has successfully completed the first science flight of the Global Hawk unpiloted aircraft system over the Pacific Ocean. The flight was the first of five scheduled for this month's Global Hawk Pacific, or GloPac, mission to study atmospheric science over the Pacific and Arctic oceans.

The Global Hawk is a robotic plane that can fly autonomously to altitudes above 18,288 meters (60,000 feet) -- roughly twice as high as a commercial airliner -- and as far as 20,372 kilometers (11,000 nautical miles), which is half the circumference of Earth. Operators pre-program a flight path, then the plane flies itself for as long as 30 hours, staying in contact through satellite and line-of-site communications links to a ground control station at NASA's Dryden Flight Research Center in California's Mojave Desert."The Global Hawk is a revolutionary aircraft for science because of its enormous range and endurance," said Paul Newman, co-mission scientist for GloPac and an atmospheric scientist from NASA's Goddard Space Flight Center in Greenbelt, Md. "No other science platform provides the range and time to sample rapidly evolving atmospheric phenomena. This mission is our first opportunity to demonstrate the unique capabilities of this plane, while gathering atmospheric data in a region that is poorly sampled."GloPac researchers plan to directly measure and sample greenhouse gases, ozone-depleting substances, aerosols and constituents of air quality in the upper troposphere and lower stratosphere. GloPac's measurements will cover longer time periods and greater geographic distances than any other science aircraft.During Wednesday's flight, the plane flew approximately 8,334 kilometers (4,500 nautical miles) along a flight path that took it to 150.3 degrees West longitude, and 54.6 degrees North latitude, just south of Alaska's Kodiak Island. The flight lasted just over 14 hours and flew up to 18,562 meters (60,900 feet). The mission is a joint project with the National Oceanic and Atmospheric Administration, or NOAA.The plane carries 11 instruments to sample the chemical composition of the troposphere and stratosphere, including two from NASA's Jet Propulsion Laboratory, Pasadena, Calif.. The instruments profile the dynamics and meteorology of both layers and observe the distribution of clouds and aerosol particles. Project scientists expect to take observations from the equator north to the Arctic Circle and west of Hawaii.Although the plane is designed to fly on its own, pilots can change its course or altitude based on interesting atmospheric phenomena ahead. Researchers have the ability via communications links to control their instruments from the ground."The Global Hawk is a fantastic platform because it gives us expanded access to the atmosphere beyond what we have with piloted aircraft," said David Fahey, co-mission scientist and a research physicist at NOAA's Earth System Research Laboratory in Boulder, Colo. "We can go to regions we couldn't reach or go to previously explored regions and study them for extended periods that are impossible with conventional planes."The timing of GloPac flights should allow scientists to observe the breakup of the polar vortex. The vortex is a large-scale cyclone in the upper troposphere and lower stratosphere that dominates winter weather patterns around the Arctic and is particularly important for understanding ozone depletion in the Northern Hemisphere.Scientists also expect to gather high-altitude data between 13,716 and 19,812 meters (45,000 and 65,000 feet), where many greenhouse gases and ozone-depleting substances are destroyed. They will measure dust, smoke and pollution that cross the Pacific from Asia and Siberia and affect U.S. air quality.Global Hawk will make several flights under NASA's Aura satellite and other "A-train" Earth-observing satellites, "allowing us to calibrate and confirm what we see from space," Newman added. GloPac is specifically being conducted in conjunction with NASA's Aura Validation Experiment.GloPac includes more than 130 researchers and technicians from Goddard, Dryden Flight Research Center, JPL, and Ames Research Center in Moffett Field, Calif. Also involved are NOAA's Earth System Research Laboratory; the University of California, Santa Cruz; Droplet Measurement Technologies of Boulder, Colo.; and the University of Denver.NASA Dryden and the Northrop Grumman Corp. of Rancho Bernardo, Calif., signed a Space Act Agreement to re-fit and maintain three Global Hawks transferred from the U.S. Air Force for use in high-altitude, long-duration Earth science missions.For more on GloPac, visit:

Ozone Holes

April 6, 2010

https://www.sciencedaily.com/releases/2010/03/100331081137.htm

Flights over Arctic provide data for investigating ozone hole depletion

An international team of researchers is investigating ozone depletion in the polar stratosphere using data gathered during flights over the Arctic region at elevations of up to 20 kilometers.

The team of atmosphere researchers -- among them Stephan Borrmann, Professor at the Institute of Atmospheric Physics of Johannes Gutenberg University Mainz and one of the directors of the Max Planck Institute of Chemistry in Mainz -- hopes to discover how long the processes that result in the formation of the hibernal holes in the ozone layer at the polar caps actually take. It is also expected that the data collected during the flights undertaken with the high-altitude aircraft "M55 Geophysica" will provide insight into what effect climate change is having on the physical and chemical processes that influence the ozone layer. This would make it possible to extrapolate the future development of the ozone layer under the conditions obtained during on-going changes.The chlorofluorocarbons (CFCs) released by humans on the surface of the earth are gradually transported into the stratosphere. Here the CFCs are exposed to powerful ultraviolet radiation which decomposes the chlorofluorocarbons to finally release chlorine. This chlorine usually reacts with other chemicals and is bound in substances such as hydrogen chloride vapor and chlorine nitrate, which are not detrimental to ozone. However, in the stratospheric clouds located over the poles, the clorine from CFCs can form aggressive ozone-destroying chlorine monoxide radicals (CIO).Analysis of these clouds is thus essential to the research being conducted by the Mainz team under Stephan Borrmann. And it is these extraordinary but natural clouds that are formed only in the stratosphere over the Arctic and Antarctic regions during the cold of the polar winters that are implicated in the formation of the holes in the ozone layer."As the warming of the atmosphere attributable to climate change also has a direct effect on the physical and chemical processes associated with the ozone layer, we urgently need to conduct new research into this aspect," explains Professor Borrmann.The scientists are able to directly analyze the properties of the particles making up these polar stratospheric clouds -- frozen droplets of ice and nitric acid with an approximate diameter of 3-20 micrometers -- using instruments attached to the aircraft. In order to be able to determine the rate and extent of ozone depletion, the scientists need to find out exactly what size these droplets are and how many of them are present in these polar stratospheric clouds (PSCs). The Mainz team is using additional instruments to evaluate the characteristics of ultrafine airborne aerosol particles that are also present in the stratosphere and play a role in the relevant processes.Remarkably, the presence of meteoric dust was even detected in the stratosphere during the data-gathering flights conducted between mid-January and mid-March 2010. It has also proved possible to collect significant amounts of data directly from PSCs. "We were amazed to discover that there were surprisingly large particles present in polar stratospheric clouds. These has a diameter of up to 30 micrometers, and they were rapidly precipitated thanks to their weight. This causes the substances contained in them to be irreversibly removed from the stratosphere, thus promoting the process of ozone depletion," Borrmann explains.Originally a Russian spy plane, M55 Geophysica is one of only three aircraft worldwide that are able to reach the stratosphere -- and it can do this while carrying a payload of nearly one ton of metering instruments and other equipment. Such flights are the only way in which the atmospheric researchers can collect the information they still need to understand the correlations between ozone depletion and climate change.Researchers from nine countries are taking part in the measuring flights, which start from Kiruna, located in the Arctic Circle in northern Sweden. The campaign is part of the EU project "RECONCILE" (reconciliation of essential parameters for an enhanced predictability of arctic stratospheric ozone loss and its climate interactions) that is being coordinated by scientists of the Jülich Research Center.

Ozone Holes

March 30, 2010

https://www.sciencedaily.com/releases/2010/03/100329203226.htm

Vital role for bacteria in climate-change gas cycle

Isoprene is a Jekyll-and-Hyde gas that is capable of both warming and cooling the Earth depending on the prevailing conditions. It is an important industrial gas, necessary for the manufacture of important compounds such as rubber and vitamins, but very little is known about how isoprene is cycled in the environment.

At the Society for General Microbiology's spring meeting in Edinburgh, Dr Terry McGenity revealed the identity of some crucial players in the gas cycle; isoprene-degrading bacteria that are able to intercept the release of isoprene into the atmosphere.After being released by plants and algae, isoprene reacts with molecules in the atmosphere to produce ozone. It can also prolong the lifetime of methane in the air. Both ozone and methane are potent greenhouse gases that lead to global warming. Conversely, in certain conditions, isoprene can undergo chemical reactions to form aerosols that can increase cloud cover leading to cooling of the Earth.Together with colleagues at the University of Essex, Dr McGenity discovered that that there are numerous types of bacteria able to consume isoprene before it even enters the atmosphere. These bacteria were found concentrated around coastal zones that are known to be hot spots of marine isoprene production by algae."The discovery will improve models that help us to predict how climate change and other environmental factors affect isoprene flux and vice versa," said Dr McGenity. "Until now modelling the overall flow of isoprene from the sea to the atmosphere has been hampered by inadequate understanding of the main producers and consumers," he explained.Interestingly, many of the isoprene-degrading bacteria can also break down alkanes (a major component of crude oil). "This suggests that algal-derived isoprene may help important oil-degrading microbes to survive between spills," explained Dr McGenity.An understanding of how isoprene is naturally cycled in the environment could have important applications across different industries. "Currently the chemical industry relies on isoprene derived from crude oil as a building block for the manufacture of compounds like vitamins and rubber, whereas algae could potentially provide a sustainable supply of isoprene for these uses." suggested Dr McGenity. "Equally, studying the enzymes involved in bacterial isoprene metabolism may lead to applications in the synthesis of important pharmaceuticals," he said.

Ozone Holes

March 26, 2010

https://www.sciencedaily.com/releases/2010/03/100325143047.htm

Pollution from Asia circles globe at stratospheric heights

The economic growth across much of Asia comes with a troubling side effect: pollutants from the region are being wafted up to the stratosphere during monsoon season. The new finding, in a study led by scientists at the National Center for Atmospheric Research, provides additional evidence of the global nature of air pollution and its effects far above Earth's surface.

The international study is being published March 26 in Using satellite observations and computer models, the research team determined that vigorous summertime circulation patterns associated with the Asian monsoon rapidly transport air upward from the Earth's surface. Those vertical movements provide a pathway for black carbon, sulfur dioxide, nitrogen oxides, and other pollutants to ascend into the stratosphere, about 20-25 miles above the Earth's surface."The monsoon is one of the most powerful atmospheric circulation systems on the planet, and it happens to form right over a heavily polluted region," says NCAR scientist William Randel, the lead author. "As a result, the monsoon provides a pathway for transporting pollutants up to the stratosphere."Once in the stratosphere, the pollutants circulate around the globe for several years. Some eventually descend back into the lower atmosphere, while others break apart.The study suggests that the impact of Asian pollutants on the stratosphere may increase in coming decades because of the growing industrial activity in China and other rapidly developing nations. In addition, climate change could alter the Asian monsoon, although it remains uncertain whether the result would be to strengthen or weaken vertical movements of air that transport pollutants into the stratosphere.Randel says more research is needed into the possible effects of the pollutants. When sulfur rises into the stratosphere, it can lead to the creation of small particles called aerosols that are known to influence the ozone layer. The monsoon transport pathway may also have effects on other gases in the stratosphere, such as water vapor, that affect global climate by influencing the amount of solar heat that reaches Earth.Tracing the path of pollutantsScientists have long known that air over the tropics moves upward between the lower atmosphere and the stratosphere, part of a large-scale pattern known as the Brewer-Dobson circulation. But Randel and his colleagues suspected that the monsoon might also transport air into the stratosphere during the Northern Hemisphere's summer months. This could explain satellite measurements showing anomalous levels of stratospheric ozone, water vapor, and other chemicals over Asia during summer.To isolate the role of the monsoon on the stratosphere, the researchers focused on a chemical, hydrogen cyanide, that is produced largely as a result of the burning of trees and other vegetation. The parcels of air over the tropical ocean that are lifted to the stratosphere by the Brewer-Dobson circulation contain low amounts of hydrogen cyanide, which breaks up over the ocean. But air over land that gets lifted up by the monsoon contains high levels of the chemical, especially during times of year when Asia has widespread fires, many set to clear land for agriculture.When they examined satellite measurements, the researchers detected significant amounts of hydrogen cyanide throughout the lower atmosphere and up into the stratosphere over the monsoon region. Furthermore, satellite records from 2004 to 2009 showed a pattern of increases in the chemical's presence in the stratosphere each summer, correlating with the timing of the monsoon. The observations also showed hydrogen cyanide, which can last in the atmosphere for several years before breaking up, moving over the tropics with other pollutants and then circulating globally.The researchers then used computer modeling to simulate the movement of hydrogen cyanide and pollutants from other sources, including industrial activity. The model indicated that emissions of pollutants over a broad region of Asia, from India to China and Indonesia, were becoming entrained in the monsoon circulation and transported into the lower stratosphere."This is a vivid example of pollutants altering our atmosphere in subtle and far-reaching ways," Randel says.In addition to the NCAR researchers, the study team included scientists from the universities of Waterloo and Toronto in Canada, the University of York in England, and the University of Edinburgh in Scotland.The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation.

Ozone Holes

March 24, 2010

https://www.sciencedaily.com/releases/2010/03/100324113543.htm

Earth's health reaching critical tipping point, expert says

With climate change at the front and center of today's political debates, the other indicators of the Earth's environmental health are not always top of mind in the public conscience.

Featured as part of the cover story of In his article, "Boundaries for a Healthy Planet," he argues that while climate change gets ample attention, species loss and nitrogen pollution exceed safe limits by greater degrees. In addition, other environmental processes such as ocean acidification and stratospheric ozone depletion are also moving toward dangerous thresholds.Foley calls for swift action to address these developments and push back from planetary "tipping points" that would thrust the global environment and human life into dangerous new territory. First steps include promptly switching to low-carbon energy sources, curtailing land clearing and revolutionizing agricultural practices.Foley is director of the University of Minnesota's Institute on the Environment. Originally trained as an atmospheric scientist, he works primarily on the nexus of land use, agriculture and the global environment.

Ozone Holes

March 16, 2010

https://www.sciencedaily.com/releases/2010/03/100316142529.htm

UV exposure has increased over the last 30 years, but stabilized since the mid-1990s

NASA scientists analyzing 30 years of satellite data have found that the amount of ultraviolet (UV) radiation reaching Earth's surface has increased markedly over the last three decades. Most of the increase has occurred in the mid-and-high latitudes, and there's been little or no increase in tropical regions.

The new analysis shows, for example, that at one line of latitude -- 32.5 degrees -- a line that runs through central Texas in the northern hemisphere and the country of Uruguay in the southern hemisphere, 305 nanometer UV levels have gone up by some 6 percent on average since 1979.The primary culprit: decreasing levels of stratospheric ozone, a colorless gas that acts as Earth's natural sunscreen by shielding the surface from damaging UV radiation.The finding reinforces previous observations that show UV levels are stabilizing after countries began signing an international treaty that limited the emissions of ozone-depleting gases in 1987. The study also shows that increased cloudiness in the southern hemisphere over the 30-year period has impacted UV.Jay Herman, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., stitched together data from several earth observing satellites -- including NASA's Aura satellite, NOAA weather satellites, and commercial satellites -- to draw his conclusions. The results were published in the "Overall, we're still not where we'd like to be with ozone, but we're on the right track," said Jay Herman. "We do still see an increase in UV on a 30-year timescale, but it's moderate, it could have been worse, and it appears to have leveled off."In the tropics, the increase has been minimal, but in the mid-latitudes it has been more obvious. During the summer, for example, UV has increased by more than 20 percent in Patagonia and the southern portions of South America. It has risen by nearly 10 percent in Buenos Aires, a city that's about the same distance from the equator as Little Rock, Ark. At Washington, D.C.'s latitude -- about 35 degrees north -- UV has increased by about 9 percent since 1979.The southern hemisphere tends to have more UV exposure because of the ozone hole, a seasonal depletion of the ozone layer centered on the South Pole. There are also fewer particles of air pollution -- which help block UV -- due to the comparatively small numbers of people who live in the southern hemisphere.Despite the overall increases, there are clear signs that ultraviolet radiation levels are on the verge of falling. Herman's analysis, which is in agreement with a World Meteorological Report published in recent years, shows that decreases in ozone and corresponding increases in UV irradiance leveled off in the mid-nineties.Shorter ultraviolet wavelengths of light contain more energy than the infrared or visible portions of sunlight that reach Earth's surface. Because of this, UV photons can break atmospheric chemical bonds and cause complex health effects.Longer wavelengths (from 320 to 400 nanometers) -- called UV-A -- cause sunburn and cataracts. Yet, UV-A can also improve health by spurring the production of Vitamin D, a substance that's critical for calcium absorption in bones and that helps stave off a variety of chronic diseases.UV-B, which has slightly shorter wavelengths (from 320 to 290 nanometers), damages DNA by tangling and distorting its ladder-like structure, causing a range of health problems such as skin cancer and diseases affecting the immune system.As part of his study, Herman developed a mathematical technique to quantify the biological impacts of UV exposure. He examined and calculated how changing levels of ozone and ultraviolet irradiance affect life. For Greenbelt, Md., for example, he calculated that a 7 percent increase in UV yielded a 4.4 percent increase in the damage to skin, a 4.8 percent increase in damage to DNA, a 5 percent increase in Vitamin D production, and less than a percent of increase in plant growth."If you go to the beach these days, you're at slightly higher risk of getting skin cancer (without protection)," Herman said, though he noted the risk would have been even greater in the absence of regulations on ozone-depleting substances.Last year, one of Herman's Goddard colleagues, Paul Newman, published a study showing that the ozone hole likely would have become a year-round fixture and UV radiation would increase 650 percent by 2065 in mid-latitude cities if not for the Montreal Protocol, an international treaty signed in 1987 that limited the amount of ozone-depleting gases countries could emit.In addition to analyzing ozone and ultraviolet trends, Herman also used satellite data to study whether changes in cloudiness have affected UV trends. To his surprise, he found that increased cloudiness in the southern hemisphere produced a dimming effect that increased the shielding from UV compared to previous years.In the higher latitudes especially, he detected a slight reduction -- typically of 2 to 4 percent -- in the amount of UV passing through the atmosphere and reaching the surface due to clouds. "It's not a large amount, but it's intriguing," Herman said. "We aren't sure what's behind it yet."Vitali Fioletov, a Canadian scientist and member of the World Meteorological Organization's advisory group on ultraviolet radiation, agreed that Herman's findings about cloudiness warrant additional investigation. "I found the cloud effects on the global scale to be the most interesting aspect of the study," he said. "This isn't something you could see without satellites."Herman synthesized measurements from the Total Ozone Mapping Spectrometer (TOMS) aboard Nimbus 7 and Earth Probe, the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite, NASA's Sea-Viewing Wide Field-of-view sensor (SeaWiFS) on the commercial SeaStar satellite, and the Solar Backscatter Ultraviolet Instrument (SBUV) on several polar orbiting NOAA weather satellites.

Ozone Holes

March 16, 2010

https://www.sciencedaily.com/releases/2010/03/100303114001.htm

Chemicals that eased one environmental problem may worsen another

Chemicals that helped solve a global environmental crisis in the 1990s -- the hole in Earth's protective ozone layer -- may be making another problem -- acid rain -- worse, scientists are reporting.

Their study on the chemicals that replaced the ozone-destroying chlorofluorocarbons (CFCs) once used in aerosol spray cans, air conditioners, refrigerators, and other products, appears in ACS' Jeffrey Gaffney, Carrie J. Christiansen, Shakeel S. Dalal, Alexander M. Mebel and Joseph S. Francisco point out that hydrochlorofluorocarbons (HCFCs) emerged as CFC replacements because they do not damage the ozone layer. However, studies later suggested the need for a replacement for the replacements, showing that HCFCs act like super greenhouse gases, 4,500 times more potent than carbon dioxide.The new study adds to those concerns, raising the possibility that HCFCs may break down in the atmosphere to form oxalic acid, one of the culprits in acid rain.They used a computer model to show how HCFCs could form oxalic acid via a series of chemical reactions high in the atmosphere. The model, they suggest, could have broader uses in helping to determine whether replacements for the replacements are as eco-friendly as they appear before manufacturers spend billions of dollars in marketing them.

Ozone Holes

March 12, 2010

https://www.sciencedaily.com/releases/2010/03/100311141213.htm

Aquatic 'dead zones' contributing to climate change

The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than just local waters. In the March 12 edition of the journal

"As the volume of hypoxic waters move towards the sea surface and expands along our coasts, their ability to produce the greenhouse gas nitrous oxide increases," explains Dr. Codispoti of the UMCES Horn Point Laboratory. "With low-oxygen waters currently producing about half of the ocean's net nitrous oxide, we could see an additional significant atmospheric increase if these 'dead zones' continue to expand."Although present in minute concentrations in Earth's atmosphere, nitrous oxide is a highly potent greenhouse gas and is becoming a key factor in stratospheric ozone destruction. For the past 400,000 years, changes in atmospheric NIncreased NNWhen suboxic waters (oxygen essentially absent) occur at depths of less than 300 feet, the combination of high respiration rates, and the peculiarities of a process called denitrification can cause N"Nitrous oxide data from many coastal zones that contain low oxygen waters are sparse, including Chesapeake Bay," said Dr. Codispoti. "We should intensify our observations of the relationship between low oxygen concentrations and nitrous oxide in coastal waters."

Ozone Holes

February 1, 2010

https://www.sciencedaily.com/releases/2010/01/100131151009.htm

Emissions of Potent Greenhouse Gas Increase Despite Reduction Efforts

Despite a decade of efforts worldwide to curb its release into the atmosphere, NOAA and university scientists have measured increased emissions of a greenhouse gas that is thousands of times more efficient at trapping heat than carbon dioxide and persists in the atmosphere for nearly 300 years.

The substance HFC-23, or trifluoromethane, is a byproduct of chlorodifluoromethane, or HCFC-22, a refrigerant in air conditioners and refrigerators and a starting material for producing heat and chemical-resistant products, cables and coatings."Without the international effort to reduce emissions of HFC-23, its emissions and atmospheric abundance would have been even larger in recent years," said Stephen Montzka, a NOAA research chemist and lead author of the collaborative study between NOAA and university scientists. "As it was, emissions in 2006-2008 were about 50 percent above the 1990-2000 average."HFC-23 is one of the most potent greenhouse gases emitted as a result of human activities. Over a 100-year time span, one pound of HFC-23 released into the atmosphere traps heat 14,800 times more effectively than one pound of carbon dioxide. To date, the total accumulated emission of HFC-23 is small relative to other greenhouse gases, making this gas a minor (less than one percent) contributor to climate change at present.Because HFC-23 is such a potent greenhouse gas, the United Nations Framework Convention on Climate Change (UNFCCC) has facilitated the destruction of substantial quantities of HFC-23 in developing countries since 2003. The study by Montzka and colleagues shows for the first time that even with these actions HFC-23 emissions from developing countries remained substantial compared to recent years.The Montreal Protocol, which is the international agreement that phases out ozone-depleting substances, requires the end of HCFC-22 production by 2020 in developed countries and 2030 in developing counties for uses that result in the HCFC-22 escaping to the atmosphere. This Protocol does not restrict HCFC-22 production in the synthesis of fluoropolymers or the HFC-23 that is co-produced. The future atmospheric abundance of HFC-23 and its contribution to future climate change depends on amounts of HCFC-22 produced and the success of programs to reduce emissions of the co-generated HFC-23.Scientists measured air collected from above the snow surface and down to 380 feet below the snow surface during field studies in Antarctica in 2001, 2005 and 2009. Using these results, they were able to determine how amounts of HFC-23 and other gases affecting climate and stratospheric ozone have changed in the recent past. The first published measurements of HFC-23 appeared in 1998 but this was the first time scientists examined how HFC-23 emissions have changed since 1996, particularly in developing nations and since the UNFCCC's projects to reduce emissions began in 2003.This study was supported in part by NOAA's Climate Program Office and the National Science Foundation.

Ozone Holes

January 26, 2010

https://www.sciencedaily.com/releases/2010/01/100125192016.htm

Ozone hole healing could cause further climate warming

The hole in the ozone layer is now steadily closing, but its repair could actually increase warming in the southern hemisphere, according to scientists at the University of Leeds.

The Antarctic ozone hole was once regarded as one of the biggest environmental threats, but the discovery of a previously undiscovered feedback shows that it has instead helped to shield this region from carbon-induced warming over the past two decades.High-speed winds in the area beneath the hole have led to the formation of brighter summertime clouds, which reflect more of the sun's powerful rays."These clouds have acted like a mirror to the sun's rays, reflecting the sun's heat away from the surface to the extent that warming from rising carbon emissions has effectively been cancelled out in this region during the summertime," said Professor Ken Carslaw of the University of Leeds who co-authored the research."If, as seems likely, these winds die down, rising COThe key to this newly-discovered feedback is aerosol -- tiny reflective particles suspended within the air that are known by experts to have a huge impact on climate.Greenhouses gases absorb infrared radiation from the Earth and release it back into the atmosphere as heat, causing the planet to warm up over time. Aerosol works against this by reflecting heat from the sun back into space, cooling the planet as it does so.Beneath the Antarctic ozone hole, high-speed winds whip up large amounts of sea spray, which contains millions of tiny salt particles. This spray then forms droplets and eventually clouds, and the increased spray over the last two decades has made these clouds brighter and more reflective.As the ozone layer recovers it is believed that this feedback mechanism could decline in effectiveness, or even be reversed, leading to accelerated warming in the southern hemisphere."Our research highlights the value of today's state-of- the-art models and long-term datasets that enable such unexpected and complex climate feedbacks to be detected and accounted for in our future predictions," added Professor Carslaw.The Leeds team made their prediction using a state-of-the-art global model of aerosols and two decades of meteorological data. The research was funded by the Natural Environment Research Council's Surface Ocean-Lower Atmosphere Study (UK SOLAS) and the Academy of Finland Centre of Excellence Programme.

Ozone Holes

January 21, 2010

https://www.sciencedaily.com/releases/2010/01/100120131252.htm

Springtime ozone increases above western North America linked to emissions from abroad

Springtime ozone levels above western North America are rising primarily due to air flowing eastward from the Pacific Ocean, a trend that is largest when the air originates in Asia.

Such increases in ozone could make it more difficult for the United States to meet Clean Air Act standards for ozone pollution at ground level, according to a new international study. Published online January 20 in the journal "In springtime, pollution from across the hemisphere, not nearby sources, contributes to the ozone increases above western North America," said lead author Owen R. Cooper, of the NOAA-funded Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder. "When air is transported from a broad region of south and east Asia, the trend is largest."The study focused on springtime ozone in a slice of the atmosphere from two to five miles above the surface of western North America, far below the protective ozone layer but above ozone-related, ground-level smog that is harmful to human health and crops. Ozone in this intermediate region constitutes the northern hemisphere background, or baseline, level of ozone in the lower atmosphere. The study was the first to pull together and analyze nearly 100,000 ozone observations gathered in separate studies by instruments on aircraft, balloons and other platforms.Combustion of fossil fuels releases pollutants like nitrogen oxides and volatile organic compounds, or VOCs, which react in the presence of sunlight to form ozone. North American emissions contribute to global ozone levels, but the researchers did not find any evidence that these local emissions are driving the increasing trend in ozone above western North America.Cooper and colleagues from NOAA's Earth System Research Laboratory in Boulder and eight other research institutes used historical data of global atmospheric wind records and sophisticated computer modeling to match each ozone measurement with air-flow patterns for several days before it was recorded. This approach essentially let the scientists track ozone-producing emissions back to a broad region of origin.This method is like imagining a box full of 40,000 tiny weightless balls at the exact location of each ozone measurement, said Cooper. Factoring in winds in the days prior to the measurement, the computer model estimates which winds brought the balls to that spot and where they originated.When the dominant airflow came from south and east Asia, the scientists saw the largest increases in ozone measurements. When airflow patterns were not directly from Asia, ozone still increased but at a lower rate, indicating the possibility that emissions from other places could be contributing to the ozone increases above North America.The study used springtime ozone measurements because previous studies have shown that air transport from Asia to North America is strongest in spring, making it easier to discern possible effects of distant pollution on the North American ozone trends.Ozone-measuring research balloons and research aircraft collected a portion of the data. Commercial flights equipped with ozone-measuring instruments also collected a large share of the data through the MOZAIC program, initiated by European scientists in 1994. The bulk of the data was collected between 1995 and 2008, but the team also included a large ozone dataset from 1984.The analysis shows an overall significant increase in springtime ozone of 14 percent from 1995 to 2008. When they included data from 1984, the year with the lowest average ozone level, the scientists saw a similar rate of increase from that time through 2008 and an overall increase in springtime ozone of 29 percent."This study did not quantify how much of the ozone increase is solely due to Asia," Cooper said. "But we can say that the background ozone entering North America increased over the past 14 years and probably over the past 25 years."The influence of ozone from Asia and other sources on ground-level air quality is a question for further study, Cooper said. Scientists will need to routinely measure ozone levels close to the surface at several locations along the West Coast to see whether similar trends are impacting ground-level air quality.Collaborating institutions include the Norwegian Institute for Air Research, the National Center of Scientific Research Midi-Pyrenees Observatory in Toulouse, France; the Meteorological Service of Canada; NASA Jet Propulsion Laboratory and the California Institute of Technology; the University of Washington; the National Center for Atmospheric Research in Boulder; and NASA's Langley Research Center in Hampton, Va.

Ozone Holes

December 14, 2009

https://www.sciencedaily.com/releases/2009/12/091214101408.htm

Ethanol-powered vehicles generate more ozone than gas-powered ones

Ethanol -- often promoted as a clean-burning, renewable fuel that could help wean the nation from oil -- would likely worsen health problems caused by ozone, compared with gasoline, especially in winter, according to a new study led by Stanford researchers.

Ozone production from both gasoline and E85, a blend of gasoline and ethanol that is 85 percent ethanol, is greater in warm sunny weather than during the cold weather and short days of winter, because heat and sunlight contribute to ozone formation. But E85 produces different byproducts of combustion than gasoline and generates substantially more aldehydes, which are precursors to ozone."What we found is that at the warmer temperatures, with E85, there is a slight increase in ozone compared to what gasoline would produce," said Diana Ginnebaugh, a doctoral candidate in civil and environmental engineering, who worked on the study. She will present the results of the study on Tuesday, Dec. 15, at the American Geophysical Union meeting in San Francisco. "But even a slight increase is a concern, especially in a place like Los Angeles, because you already have episodes of high ozone that you have to be concerned about, so you don't want any increase."But it was at colder temperatures, below freezing, that it appeared the health impacts of E85 would be felt most strongly."We found a pretty substantial increase in ozone production from E85 at cold temperatures, relative to gasoline when emissions and atmospheric chemistry alone were considered," Ginnebaugh said. Although ozone is generally lower under cold-temperature winter conditions, "If you switched to E85, suddenly you could have a place like Denver exceeding ozone health-effects limits and then they would have a health concern that they don't have now."The problem with cold weather emissions arises because the catalytic converters used on vehicles have to warm up before they reach full efficiency. So until they get warm, a larger proportion of pollutants escapes from the tailpipe into the air.There are other pollutants that would increase in the atmosphere from burning E85 instead of gasoline, some of which are irritants to eyes, throats and lungs, and can also damage crops, but the aldehydes are the biggest contributors to ozone production, as well as being carcinogenic.Ginnebaugh worked with Mark Z. Jacobson, professor of civil and environmental engineering, using vehicle emissions data from some earlier studies and applying it to the Los Angeles area to model the likely output of pollutants from vehicles.Because E85 is only now beginning to be used in mass-produced vehicles, the researchers projected for the year 2020, when more "flex fuel" vehicles, which can run on E85, will likely be in use. They estimated that vehicle emissions would be about 60 percent less than today, because automotive technology will likely continue to become cleaner over time. They investigated two scenarios, one that had all the vehicles running on E85 and another in which the vehicles all ran on gasoline.Running a widely used, complex model involving over 13,000 chemical reactions, they did repeated simulations at different ambient temperatures for the two scenarios, each time simulating a 48-hour period. They used the average ozone concentrations during each of those periods for comparison.They found that at warm temperatures, from freezing up to 41 degrees Celsius (give F conversion), in bright sunlight, E85 raised the concentration of ozone in the air by up to 7 parts per billion more than produced by gasoline. At cold temperatures, from freezing down to minus 37 degrees Celsius, they found E85 raised ozone concentrations by up to 39 parts per billion more than gasoline."What we are saying with these results is that you see an increase," Ginnebaugh said. "We are not saying that this is the exact magnitude you are going to get in a given urban area, because it is really going to vary from city to city depending on a lot of other factors such as the amount of natural vegetation, traffic levels, and local weather patterns."Ginnebaugh said the results of the study represent a preliminary analysis of the impact of E85. More data from studies of the emissions of flex fuel vehicles at various temperatures would help refine the estimates, she said.Paul Livingstone contributed to the study while he was a postdoctoral researcher in civil and environmental engineering. He now works for the California Air Resources Board.

Ozone Holes

December 9, 2009

https://www.sciencedaily.com/releases/2009/12/091207143353.htm

Snowflake chemistry could give clues about ozone depletion

There is more to the snowflake than its ability to delight schoolchildren and snarl traffic.

The structure of the frosty flakes also fascinate ice chemists like Purdue University's Travis Knepp, a doctoral candidate in analytical chemistry who studies the basics of snowflake structure to gain more insight into the dynamics of ground-level, or "tropospheric," ozone depletion in the Arctic."A lot of chemistry occurs on ice surfaces," Knepp said. "By better understanding the physical structure of the snow crystal -- how it grows and why it takes a certain shape -- we can get a better idea of the chemistry that occurs on that surface."His work on snowflake shape and how temperature and humidity affect it takes place in a special laboratory chamber no larger than a small refrigerator. Knepp can "grow" snow crystals year-round on a string inside this chamber. The chamber's temperature ranges from 100-110 degrees Fahrenheit down to minus 50 degrees Fahrenheit.Knepp, under the direction of Paul Shepson, professor and head of Purdue's Department of Chemistry, is studying snow crystals and why sharp transitions in shape occur at different temperatures. The differences he sees not only explain why no two snowflakes are identical, but also hold implications for his ozone research in the Arctic Ocean region."On the surface of all ice is a very thin layer of liquid water," Knepp said. "Even if you're well below the freezing point of water, you'll have this very thin layer of water that exists as a liquid form. That's why ice is slippery. Whenever you slip, you're not slipping on ice, you're slipping on that thin layer of water."This thin, or quasi-liquid, layer of water exists on the top and sides of a snow crystal. Its presence causes the crystal to take on different forms as temperature and humidity change.For example, the sides of a crystal growing in a warmer range of 27-32 degrees Fahrenheit expand much faster than the top or bottom, causing it to take on a platelike structure. Between 14 and 27 degrees Fahrenheit, crystals look like tall, solid prisms or needles."As you increase the humidity, you'll get more branching," Knepp said.Snow crystals transition to other shapes, and sometimes even back and forth, as the temperature and humidity change."The bottom line is that the thickness or the presence of this really thin layer of water is what dictates the general shape that the snow crystal takes," Knepp said. "By altering the quasi-liquid layer's thickness, we changed the temperature at which the snow crystal changes shape."Until now, nobody knew that the quasi-liquid layer had such a significant role in determining the shape of snow crystals. Our research clearly shows this to be the case."This knowledge has application for Knepp and his colleagues in their ozone work."Most people have probably heard of ozone depletion in the North and South Poles. This occurs in the stratosphere, about 15 miles up," Knepp said. "What people don't know is that we also see ozone levels decrease significantly at ground level."Ground-level ozone is very important. It gives the atmosphere the ability to clean itself. However, it also is toxic to humans and vegetation at high concentrations, like those found in smog, Shepson said.Complex chemical reactions regularly take place on the snow's surface. These reactions, which involve the thin layer of water found on the surface of snow crystals, cause the release of certain chemicals that reduce ozone at ground level."How fast these reactions occur is partially limited by the snow crystals' surface area," Knepp said. "Snow crystals with more branching will have higher surface areas than non-branched snow crystals, which will allow the rate of reaction to increase."The need to understand these intricate chemical reactions and their implications for ozone reduction drive the researchers to continue studying snow."As the impact of emissions from human activities continues to grow, we need to be able to understand the impact of global average ozone," Shepson said. "Understanding ice and snow is part of that."Knepp's research was published Oct. 16 in the online journal .

Ozone Holes

December 3, 2009

https://www.sciencedaily.com/releases/2009/12/091203101420.htm

Rising Antarctic snowmelt forcast

The 30-year record low in Antarctic snowmelt that occurred during the 2008-09 austral summer was likely due to concurrent strong positive phases for two main climate drivers, ENSO (El Niño -- Southern Oscillation) and SAM (Southern Hemisphere Annular Mode), according to Dr. Marco Tedesco, Assistant Professor of Earth & Atmospheric Sciences at The City College of New York.

Professor Tedesco, who is also on the doctoral faculty at the CUNY Graduate Center, added that Antarctic snowmelt levels should revert to higher norms as one of the drivers, the SAM, subsides as the damage to the ozone layer is repaired. His conclusions, which are based on space-borne microwave observations between 1979 and 2009, were reported in "The study's goal was not only to report on melting but also on the relationship between melting and the climate drivers, El Niño and the SAM," he explained. Low melt years during the 1979-2009 satellite record are related to the strength of the westerly winds that encircle Antarctica, known as the Southern Hemisphere Annular Mode (SAM)."When the SAM is in a positive phase -- meaning that the belt of winds is stronger than average -- it has a cooling effect on Antarctic surface temperatures," he explained. "The SAM was especially strong in austral spring and summer 2008-2009, and subsequently the 2008-2009 snowmelt was lower than normal."During the past 30-40 years, the SAM has gradually strengthened during austral summer, due mainly to human-caused stratospheric ozone depletion, he continued. However, as the hole is repaired as a result of compliance with the Montreal protocol, the winds will weaken and Antarctica will be subject to more warming air.The increasing summer SAM trends are projected to subside, he added. "It is likely that summer temperature increases over Antarctica will become stronger and more widespread because the warming effect from greenhouse gas increases will no longer be kept by the weakened circumpolar winds. The bottom line is as the ozone layer recovers we'll likely have more melting on Antarctica."According to Professor Tedesco, variability in El Niño and the SAM account for up to 50 percent of the variations in Antarctic snowmelt. However, the melting trends over the whole continent derived from satellite data are not statistically significant, he noted."If you add one year of data, the trend could shift from positive to negative or vice versa. Thirty years is not enough to tell the overall trend for Antarctica." However, he noted that studies based on land observations with data going back to the 1950s support a warming trend, especially on the Antarctic Peninsula.

Ozone Holes

December 1, 2009

https://www.sciencedaily.com/releases/2009/11/091130192921.htm

First comprehensive review of the state of Antarctica's climate

The first comprehensive review of the state of Antarctica's climate and its relationship to the global climate system is published Dec. 1, 2009 by the Scientific Committee on Antarctic Research (SCAR). The review --

Based on the latest evidence from 100 world-leading scientists from 13 countries, the review focuses on the impact and consequences of rapid warming of the Antarctic Peninsula and the Southern Ocean; rapid ice loss in parts of Antarctica and the increase in sea ice around the continent; the impact of climate change on Antarctica's plants and animals; the unprecedented increase in carbon dioxide levels; the connections between human-induced global change and natural variability; and the extraordinary finding that the ozone hole has shielded most of Antarctica from global warming.Dr. Colin Summerhayes, Executive Director of the Scientific Committee on Antarctic Research said, "Antarctica is an unrivalled source of information about our planet. This review describes what we know now and illustrates how human activity is driving rapid climate change. By integrating this multidisciplinary evidence into a single source we will help scientists and policy makers understand the distinction between environmental changes linked to the Earth's natural cycles, and those that are human induced. The work is particularly important because it puts Antarctic climate change into context and reveals the impact on the rest of the planet."Professor John Turner of British Antarctic Survey is the lead editor of the review. He said: "For me the most astonishing evidence is the way that one man-made environmental impact -- the ozone hole -- has shielded most of Antarctica from another -- global warming. Understanding the complexities surrounding these issues is a challenge for scientists -- and communicating these in a meaningful way to society and to policymakers is essential. There is no doubt that our world is changing and human activity is accelerating global change. This review is a major step forward in making sure that the latest and best evidence is available in one place. It sets the scene for future Antarctic Research and provides the knowledge that we all need to help us live with environmental change."This review draws together important information from different scientific disciplines (such as meteorology, glaciology and biology) and therefore different aspects of the global climate system.Key findings from the review are highlighted in 85 key points, which you can see in full at: A summary of the report's findings are detailed in the following 10 key points:The ozone hole has delayed the impact of greenhouse gas increases on the climate of the continent. Consequently south polar winds (the polar vortex), have intensified and affected Antarctic weather patterns. Westerly winds over the Southern Ocean that surrounds Antarctica have increased by around 15%. The stronger winds have effectively isolated Antarctica from the warming elsewhere on the planet. As a result during the past 30 years there has been little change in surface temperature over much of the vast Antarctic continent, although West Antarctica has warmed slightly. An important exception is the eastern coast of the Antarctic Peninsula, which has seen rapid summer warming. This warming is caused by stronger westerly winds bringing warm, wet air into the region from the ocean.The largest ocean current on Earth (the Antarctic Circumpolar Current) has warmed faster than the global ocean as a whole. The Southern Ocean is one of the major sinks of atmospheric CO2, but increasing westerly winds have affected the ocean's ability to absorb CO2 by causing the upwelling of CO2 rich water. If temperatures continue to rise 'alien' species may migrate into the region, competing with and replacing original Antarctic inhabitants. Key species in the food chain like planktonic snails could suffer from ocean acidification. Changes in the food regime are likely to decrease the rich Antarctic seabed biodiversity.Rapid warming has been seen along the western Antarctic Peninsula, along with a switch from snowfall to rain during summer, resulting in expansion of plant, animal and microbial communities in newly available land. Humans have also inadvertently introduced 'alien' organisms such as grasses, flies and bacteria.The West Antarctic Ice Sheet has significantly thinned particularly around the Amundsen Sea Embayment as a result of warmer ocean temperatures. Regional warming caused by intensification of the westerly winds (due to the ozone hole) is melting ice shelves along the eastern Antarctic Peninsula (e.g. Larsen B Ice Shelf). Overall, 90% of the Peninsula's glaciers have retreated in recent decades. However, the bulk of the Antarctic ice sheet has shown little change.Since 1980 there has been a 10% increase in Antarctic sea ice extent, particularly in the Ross Sea region, as a result of the stronger winds around the continent (due to the ozone hole). In contrast, regional sea ice has decreased west of the Antarctic Peninsula due to changes in local atmospheric circulation and this has also been linked with the very rapid warming seen over land on the west coast of the Peninsula.Atmospheric concentrations of CO2 and CH4 are at higher levels than experienced in the last 800,000 years and are increasing at rates unlikely to have been seen in the (geologically) recent past. Antarctica was warmer in the last interglacial (130,000 years ago) and sea levels were higher, but the contribution of West Antarctica to that rise is currently unknown. Small-scale climate variability over the last 11,000 years has caused rapid ice loss, shifts in ocean and atmospheric circulation and enhanced biological production, showing that Antarctica is highly sensitive to even minor climate changes. Studies of sediments under recently lost ice shelves suggest ice shelf loss in some regions is unprecedented during this time scale.Loss of sea ice west of the Antarctic Peninsula has caused changes in algal growth. This loss of sea ice has also caused a shift from large to smaller species. Stocks of krill have declined significantly. In some areas Adélie penguin populations have declined due to reduced sea ice and prey species (on the northern Antarctic Peninsula), but they have remained stable or increased elsewhere (Ross Sea and East Antarctica). Historical exploitation of seals and whales has changed the ecosystem, reducing scientists' ability to fully understand the impacts of climate change on krill and other species.Over this century the ozone hole is expected to heal, allowing the full effects of greenhouse gas increases to be felt across the Antarctic. Models suggest that the net effect will be continued slow strengthening of winds across the Southern Ocean, while sea ice will decrease by a third, resulting in increased phytoplankton productivity. The predicted warming of about 3°C across the continent is not enough to melt the main ice sheet and an increase in snowfall there should offset sea level rise by a few centimetres.Loss of ice from the West Antarctic ice sheet is likely to contribute some tens of centimetres to global sea level by 2100. This will contribute to a projected total sea level rise of up to 1.4 metres (and possibly higher) by 2100.Climate variability in the Polar Regions is larger than in other parts of the world, yet these remote regions are sparsely sampled. These areas need to be monitored in much greater detail in order to detect change, to improve understanding of the processes at work, and to distinguish between natural climate variability and variability caused by human influences. A detailed understanding of past climate is also crucial for understanding this distinction, as is a significant refinement of currently crude climate models.Scientific Committee on Antarctic Research (SCAR) is the main body dealing with the international co-ordination of scientific research in Antarctica and the Southern Ocean. Formed with 12 member countries in 1958 to continue activities begun during the International Geophysical Year of 1957 -- 58, it is an interdisciplinary committee of the International Council for Science (ICSU) and now has 35 Member countries. SCAR played a leading role in the recently completed International Polar Year (2007 -- 2008).

Ozone Holes

November 17, 2009

https://www.sciencedaily.com/releases/2009/11/091116143619.htm

Glimpsing a greener future: Computer model foresees effects of alternative transportation fuels

It's the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor.

Look into Shane Stephens-Romero's crystal ball -- a computer model called STREET -- and find that air quality has significantly improved. Greenhouse gas emissions are more than 60 percent lower than in 2009, and levels of microscopic soot and ozone are about 15 percent and 10 percent lower, respectively."For the first time, we can look at these future fuel scenarios and say how they're going to impact things like ozone and particulate matter, which have severe effects on people's lungs and quality of life," said Stephens-Romero, a UC Irvine doctoral candidate in the Advanced Power & Energy Program.His 2060 analysis appeared online recently in "We're transitioning to new technologies. How do we do this while maintaining our lifestyle and keeping our economy robust?" Stephens-Romero said. "We don't know how these changes could affect the future."The Spatially & Temporally Resolved Energy & Environment Tool, he says, can help.STREET considers variables in extreme detail -- not just which fuel vehicles will use but how the fuel is made, where it comes from, how it's transported and along which routes, and where fueling stations might be located.The computer model also can determine what changes must occur to achieve a desired result. For example, to bring pollution below federal limits, what percentage of the vehicle fleet would need to run on alternative fuel?"California policymakers could use the tool in this way to improve air quality in the region," Stephens-Romero said.Scott Samuelsen, director of the Advanced Power & Energy Program, says Stephens-Romero's work is getting high praise from leaders at Toyota, Honda, General Motors, Shell, Air Products, the California Air Resources Board and the California Energy Commission."The research is well positioned," Samuelsen said, "considering the development of a hydrogen infrastructure is at the crossroads of global climate change, the future of the automobile, the state economy, and California's leadership in addressing the conflict between energy and the environment."Samuelsen led the development of UCI's hydrogen fueling station, the most technologically advanced, publicly accessible station in the world. It was the first of its kind in Orange County and is a key component of the California Hydrogen Highway Network.In addition to Stephens-Romero and Samuelsen, UCI scientists Marc Carreras-Sospedra, Jack Brouwer and Donald Dabdub worked on the 2060 study, which was funded in part by the U.S. Department of Energy.

Ozone Holes

November 16, 2009

https://www.sciencedaily.com/releases/2009/11/091116085057.htm

Tiny bubbles clean oil from water

Small amounts of oil leave a fluorescent sheen on polluted water. Oil sheen is hard to remove, even when the water is aerated with ozone or filtered through sand. Now, a University of Utah engineer has developed an inexpensive new method to remove oil sheen by repeatedly pressurizing and depressurizing ozone gas, creating microscopic bubbles that attack the oil so it can be removed by sand filters.

"We are not trying to treat the entire hydrocarbon [oil] content in the water -- to turn it into carbon dioxide and water -- but we are converting it into a form that can be retained by sand filtration, which is a conventional and economical process," says Andy Hong, a professor of civil and environmental engineering.In laboratory experiments reported recently online in the journal Hong says the method -- for which patents are pending -- also could be used to clean a variety of pollutants in water and even soil, including:Hong conducted the study with two University of Utah doctoral students -- Zhixiong Cha, who has earned his Ph.D., and Chia-Jung Cheng -- and with Cheng-Fang Lin, an environmental engineering professor at National Taiwan University.Zapping Oily Water with Microbubbles from Ozone under PressureHong says his method uses two existing technologies -- ozone aeration and sand filtration -- and adds a big change to the former. Instead of just bubbling ozone through polluted water, Hong uses repeated cycles of pressurization of ozone and dirty water so the ozone saturates the water, followed by depressurization so the ozone expands into numerous microbubbles in the polluted water, similar to the way a carbonated beverage foams and overflows if opened quickly.The tiny bubbles provide much more surface area -- compared with larger bubbles from normal ozone aeration -- for the oxygen in ozone to react chemically with oil. Hong says pollutants tend to accumulate on the bubbles because they are not very water-soluble. The ozone in the bubble attacks certain pollutants because it is a strong oxidant.The reactions convert most of the dispersed oil droplets -- which float on water to cause sheen -- into acids and chemicals known as aldehydes and ketones. Most of those substances, in turn, help the remaining oil droplets clump together so they can be removed by conventional sand filtration, he adds.In his study, Hong showed the new method not only removes oil sheen, but also leaves the treated water so that any remaining acids, aldehydes and ketones are more vulnerable to being biodegraded by pollution-eating microbes."These are much more biodegradable than the parent compounds," he says.Hong says the water is clean enough to be discharged after the ozonation and sand filtration, but that some pollution sources may want to use conventional methods to biodegrade remaining dissolved organic material.Details of the ExperimentsHong conducted his experiments using a tabletop chemical reactor that contained about a quart of oily water made by mixing deionized water with crude oil from the Rangely oil field in northwestern Colorado.Ozone was produced by passing dry air through a high-voltage field, converting oxygen gas, which has two oxygen atoms, into ozone, which has three.The ozone was pressurized to 10 times atmospheric pressure, about 150 pounds per square inch, which compares with inflation pressures of about 100 PSI for Hong's bicycle and 35 to 40 PSI for many automobile tires.He found oily water was cleaned most effectively by pressurizing and depressurizing it with ozone gas 10 times, then filtering it through sand, then putting the water through 20 more pressurized ozone cycles, and then filtering it again through sand. That was at flow rates of 10 to 20 liters per minute [about 2.6 to 5.3 U.S. gallons per minute] in his laboratory apparatus.Hong tested how well the ozonation worked by measuring chemical and biological oxygen demands of treated water samples. Both indirectly measure organic contents in the water. Hong also used mass spectrometry to identify what contaminants remained in the water.He found that his most effective procedure removed 99 percent of the turbidity from the "produced water" -- leaving it almost as clear as drinking water -- and removed 83 percent of the oil, converting the rest to dissolved organic acids removable by biodegradation.A Tryout in ChinaWith success in the laboratory, Hong now plans for larger-scale pilot tests."It is economical and it can be scaled up," he says.One such test will be done in Wuxi, China, where a prototype desk-sized device capable of treating 200 liters [53 U.S. gallons] at a time will be tested at three to five polluted industrial sites that the government vacated for redevelopment, Hong says.Meanwhile, the University of Utah Research Foundation has entered into options to license the technology to Miracotech, Inc., of Albany, Calif., and 7Rev, L.P., a Salt Lake City venture capital group, so the companies can bring the technology to market.Hong says other methods of treating oil well "produced water" have met with varying degrees of success. They include centrifuges, membranes, regular ozonation and air bubbles to float off contaminants. But all have drawbacks, such as inability to handle dissolved oil or high levels of oil, or susceptibility to quickly getting fouled by the oil.Neither ozonation nor sand filtration alone has been able to effectively treat oily "produced water." Hong says long-chain oil molecules don't react with ozone easily without his pressure treatment. And sand filters alone cannot remove oil.

Ozone Holes

November 6, 2009

https://www.sciencedaily.com/releases/2009/10/091030100022.htm

Lightning's 'NOx-ious' Impact On Pollution, Climate

Every year, scientists learn something new about the inner workings of lightning.

With satellites, they have discovered that more than 1.2 billion lightning flashes occur around the world every year. (Rwanda has the most flashes per square kilometer, while flashes are rare in polar regions.) Laboratory and field experiments have revealed that the core of some lightning bolts reaches 30,000 Kelvin (53,540 ºF), a temperature hot enough to instantly melt sand and break oxygen and nitrogen molecules into individual atoms.And then there is this: each of those billion lightning flashes produces a puff of nitrogen oxide gas (NOx) that reacts with sunlight and other gases in the atmosphere to produce ozone. Near Earth's surface, ozone can harm human and plant health; higher in the atmosphere, it is a potent greenhouse gas; and in the stratosphere, its blocks cancer-causing ultraviolet radiation.In 1827, the German chemist Justin von Liebig first observed that lightning produced NOx -- scientific shorthand for a gaseous mixture of nitrogen and oxygen that includes nitric oxide (NO) and nitrogen dioxide (NOFossil fuel combustion, microbes in the soil, lightning, and forest fires all produce NOx. Scientists think lightning's contribution to Earth's NOx budget -- probably about 10 percent -- is relatively small compared to fossil fuel emissions. Yet they haven't been sure whether global estimates of NOx produced by lightning are accurate."There's still a lot of uncertainty about how much NOx lightning produces," said Kenneth Pickering, an atmospheric scientist who studies lightning at NASA's Goddard Space Flight Center in Greenbelt, Md. "Indeed, even recent published estimates of lightning's global NOx production still vary by as much as a factor of four. We're trying to narrow that uncertainty in order to improve the accuracy of both global climate models and regional air quality models."Using data gleaned from aircraft observations and satellites, Pickering and Goddard colleague Lesley Ott recently took steps toward a better global estimate of lightning-produced NOx and found that lightning may have a considerably stronger impact on the climate in the mid-latitudes and subtropics -- and less on surface air quality -- than previously thought.According to a new paper by Ott and Pickering in the When the researchers multiplied the number of lightning strokes worldwide by 7 kilograms, they found that the total amount of NOx produced by lightning per year is 8.6 terragrams, or 8.6 million metric tons. "That's somewhat high compared to previous estimates," said Pickering.More remarkable than the number, however, is where the NOx is produced. A decade ago, many researchers believed cloud-to-ground lightning produced far more NOx per flash than intracloud lightning, which occurs within a cloud and far higher in the atmosphere.The new evidence suggests that the two types of lightning produce approximately the same amount of NOx per flash on average. But since most lightning is intracloud, this suggests a great deal more NOx is produced and remains higher in the atmosphere. Compounding this effect, the research also shows that strong updrafts within thunderstorms help transfer lower level NOx to higher altitudes in the atmosphere."We've really started to question some of our old assumptions as we've gotten better at measuring lightning in the field," said Ott.The observations spring out of field projects conducted in Germany, Colorado, Florida, Kansas, and Oklahoma between 1985 and 2002. For example, in a NASA field campaign called the Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida -- Florida Area Cirrus Experiment (CRYSTAL-FACE) aircraft flew headlong through anvil-shaped thunderheads to measure the anatomy of the thunderstorms. Sensors sampled the pressure, humidity, temperature, wind, and the amount of trace gases such as NOx and ozone.Later, Ott input this data, as well as additional data from the U.S. National Lightning Detection Network and NASA's Total Ozone Mapping Spectrometer (TOMS), into a complex computer model that simulated the six storms and calculated the amount of NOx that the average flash of lightning produced. With that number, she could then estimate the amount of NOx that lightning produces globally each year."One of the things we're trying to understand is how much ozone changes caused by lightning affect radiative forcing, and how that might translate into climate impacts," said Pickering.There's a possibility that lightning could produce a feedback cycle that accelerates global warming. "If a warming globe creates more thunderstorms," Pickering noted, "that could lead to more NOx production, which leads to more ozone, more radiative forcing, and more warming," Pickering emphasizes that this is a theory, and while some global modeling studies suggest this is indeed the case, it has not yet been borne out by field observations.The new findings also have implications for regional air quality models. Scientists from the U.S. Environmental Protection Agency (EPA), for example, are already plugging the new numbers into a widely-used air quality model called the Community Multi-scale Air Quality Model. "Lightning is one of the smaller factors for surface ozone levels, but in some cases a surge of ozone formed from lightning NOx could be enough to put a community out of compliance with EPA air quality standards during certain times of the year," said Pickering.Pickering offered one important caveat to the findings: The value of 7 kilograms per flash was derived without consideration of lightning from storms in the tropics, where most of the Earth's lightning occurs. Only very recently have data become available for tropical regions, he noted.

Ozone Holes

November 2, 2009

https://www.sciencedaily.com/releases/2009/11/091102171728.htm

Links Between City Walkability And Air Pollution Exposure Revealed

A new study compares neighborhoods' walkability (degree of ease for walking) with local levels of air pollution and finds that some neighborhoods might be good for walking, but have poor air quality. Researchers involved in the study include University of Minnesota faculty member Julian Marshall and University of British Columbia faculty Michael Brauer and Lawrence Frank.

The findings highlight the need for urban design to consider both walkability and air pollution, recognizing that neighborhoods with high levels of one pollutant may have low levels of another pollutant.The study, done for the city of Vancouver, British Columbia, is the first of its kind to compare the two environmental attributes, and suggests potential environmental health effects of neighborhood location, layout and design for cities around the globe.The research study is published in the November 2009 issue of The research team found that, on average, neighborhoods downtown are more walkable and have high levels of some pollutants, while suburban locations are less walkable and have high levels of different pollutants. Neighborhoods that fare well for pollution and walkability tend to be a few miles away from the downtown area. These "win-win" urban residential neighborhoods--which avoid the downtown and the suburban air pollution plus exhibit good walkability--are rare, containing only about two percent of the population studied. Census data indicate that these neighborhoods are relatively high-income, suggesting that they are desirable places to live. Neighborhoods that fare poorly for both pollution and walkability tend to be in the suburbs and are generally middle-income."Research has shown that exposure to air pollution adversely affects human health by triggering or exacerbating a number of health issues such as asthma and heart disease," said Marshall, a civil engineering faculty member in the University of Minnesota's Institute of Technology. "Likewise, physical inactivity is linked to an array of negative health effects including heart disease and diabetes. Neighborhood design can influence air pollution and walkability; more walkable neighborhoods may encourage higher daily activity levels."In the study, researchers evaluated concentrations of nitric oxide, a marker of motor vehicle exhaust, and ozone, a pollutant formed when vehicle exhaust and other pollutants react, for 49,702 postal codes (89 percent of all postal codes) in Vancouver. The researchers assigned a walkability score by analyzing four common attributes of neighborhood design: land-use mixing, intersection density, population density and for retail areas, the relative amount of land area for shopping versus for parking.More walkable neighborhoods tend to have mixed land uses, with destinations such as stores and shops within walking distance of people's houses. A conventional street grid and other more walkable road networks tend to have a higher intersection density, while less walkable neighborhoods often have circuitous road networks and low intersection density, thereby increasing average travel distances and reducing the likelihood that people will walk. More walkable areas generally have higher population density. Finally, in less walkable areas, stores devote a greater fraction of their land to parking."The finding that nitric oxide concentrations are highest downtown, while ozone concentrations are highest in the suburbs, is not surprising," said Marshall. "Motor vehicle exhaust is most concentrated downtown, leading to the high nitric oxide concentrations downtown. In contrast, ozone takes time to form. Air masses have moved away from downtown--often, to suburban areas--by the time ozone concentrations reach their highest levels. Thus, reductions in vehicle emissions can benefit people who live near high-traffic areas and also people living in less dense areas."Creating neighborhoods that are more walkable and that allow for alternative travel modes such as walking, biking or public transportation is one approach to reducing motor vehicle emissions, the study suggests. Another approach is reducing emissions per vehicle, for example through mandated emission standards. The research did not study conditions for individual people, but points out that high-rise buildings may allow people to live in walkable neighborhoods while being somewhat removed from street-level vehicle emissions.The study's new findings indicate that neighborhood design is an important consideration for improving pollution levels and providing opportunities for daily physical activity. The study identified neighborhoods that are walkable yet have low levels of pollution, but those neighborhoods encompass a very small percentage of the population. Researchers hope that future investigation of those "win-win" neighborhoods will suggest urban design features that could usefully be applied elsewhere.In the future, the researchers hope to investigate changes over time in pollution and walkability, and also study other urban areas to see how spatial patterns may differ elsewhere.

Ozone Holes

October 6, 2009

https://www.sciencedaily.com/releases/2009/10/091005123038.htm

Air Pollution May Trigger Appendicitis

A new study in

The study, conducted by researchers at the University of Calgary, University of Toronto and Health Canada, looked at 5191 adults admitted to hospital in Calgary, Alberta, Canada. Fifty-two per cent of admissions occurred between April and September, the warmest months of the year in Canada during which people are more likely to be outside.The dominant theory of the cause of appendicitis has been obstruction of the appendix opening, but this theory does not explain the trends of appendicitis in developed and developing countries. Appendicitis cases increased dramatically in industrialized countries in the 19th and early 20th centuries, then decreased in the middle and late 20th century, coinciding with legislation to improve air quality. The incidence of appendicitis has been growing in developing countries as they become more industrialized.Using Environment Canada's air pollution data for Calgary, the researchers determined the levels of ozone, nitrogen dioxide and other air-borne pollutants along with temperature. They found correlations between high levels of ozone and nitrogen dioxide and the incidence of appendicitis between age groups and genders. More men than women were found to have the condition."For unexplained reasons, men are more likely than women to have appendicitis," write Dr. Gilaad Kaplan of the University of Calgary and coauthors. "Men may be more susceptible to the effects of outdoor air pollution because they are more likely to be employed in outdoor occupations," although they note that misclassifications of data could explain some of the difference.While it is not known how air pollution may increase the risk of appendicitis, the authors suggest pollutants may trigger inflammatory responses. They recommend further studies to determine the link.

Ozone Holes

September 30, 2009

https://www.sciencedaily.com/releases/2009/09/090929132509.htm

Air Pollutants From Abroad A Growing Concern, Says New Report

Plumes of harmful air pollutants can be transported across oceans and continents -- from Asia to the United States and from the United States to Europe -- and have a negative impact on air quality far from their original sources, says a new report by the National Research Council. Although degraded air quality is nearly always dominated by local emissions, the influence of non-domestic pollution sources may grow as emissions from developing countries increase and become relatively more important as a result of tightening environmental protection standards in industrialized countries.

"Air pollution does not recognize national borders; the atmosphere connects distant regions of our planet," said Charles Kolb, chair of the committee that wrote the report and president and chief executive officer of Aerodyne Research Inc. "Emissions within any one country can affect human and ecosystem health in countries far downwind. While it is difficult to quantify these influences, in some cases the impacts are significant from regulatory and public health perspectives."The report examines four types of air pollutants: ozone; particulate matter such as dust, sulfates, or soot; mercury; and persistent organic pollutants such as DDT. The committee found evidence, including satellite observations, that these four types of pollutants can be transported aloft across the Northern Hemisphere, delivering significant concentrations to downwind continents. Ultimately, most pollutants' impacts depend on how they filter down to the surface.Current limitations in modeling and observational capabilities make it difficult to determine how global sources of pollution affect air quality and ecosystems in downwind locations and distinguish the domestic and foreign components of observed pollutants. Yet, some pollutant plumes observed in the U.S. can be attributed unambiguously to sources in Asia based on meteorological and chemical analyses, the committee said. For example, one study found that a polluted airmass detected at Mt. Bachelor Observatory in central Oregon took approximately eight days to travel from East Asia.The health impacts of long-range transport vary by pollutant. For ozone and particulate matter -- which cause respiratory problems and other health effects -- the main concern is direct inhalation. While the amount of ozone and particulate matter transported on international scales is generally quite small compared with domestic sources, neither of these pollutants has a known "threshold," or concentration below which exposure poses no risk for health impacts. Therefore, even small incremental increases in atmospheric concentrations can have negative impacts, the committee said. For instance, modeling studies have estimated that about 500 premature cardiopulmonary deaths could be avoided annually in North America by reducing ozone precursor emissions by 20 percent in the other major industrial regions of the Northern Hemisphere.For mercury and persistent organic pollutants, the main health concern is that their transport and deposition leads to gradual accumulation on land and in watersheds, creating an increase in human exposure via the food chain. For example, people may consume mercury by eating fish. There is also concern about eventual re-release of "legacy" emissions that have been stored in soils, forests, snowpacks, and other environmental reservoirs.In addition, the committee said that projected climate change will lead to a warmer climate and shifts in atmospheric circulation, likely affecting the patterns of emission, transport, transformation, and deposition for all types of pollution. However, predicting the net impacts of the potential changes is extremely difficult with present knowledge.In the coming decades, man-made emissions are expected to rise in East Asia, the report says. These increases could potentially be mitigated by increasingly stringent pollution control efforts and international cooperation in developing and deploying pollution control technology.To enhance understanding of long-range transport of pollution and its impacts, the committee recommended a variety of research initiatives, such as advancing "fingerprinting" techniques to better identify source-specific pollutant characteristics, and examining how emissions from ships and aircraft affect atmospheric composition and complicate the detection of pollution from land-based sources. The committee emphasized developing an integrated "pollution source-attribution" system that improves capabilities in emissions measurements and estimates; atmospheric chemical and meteorological modeling; long-term, ground-based observations; satellite remote sensing; and process-focused field studies.Moreover, the committee stressed that the United States, as both a source and receptor of long-range pollution, has an interest in remaining actively engaged in air pollutants that travel abroad, including support of more extensive international cooperation in research, assessment, and emissions control efforts.The report was sponsored by the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, NASA, and National Science Foundation. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies.The report,

Ozone Holes

September 22, 2009

https://www.sciencedaily.com/releases/2009/09/090921134831.htm

Ozone Layer Depletion Leveling Off, Satellite Data Show

By merging more than a decade of atmospheric data from European satellites, scientists have compiled a homogeneous long-term ozone record that allows them to monitor total ozone trends on a global scale – and the findings look promising.

Scientists merged monthly total ozone data derived from the vertically downward-looking measurements of the GOME instrument on ESA’s ERS-2 satellite, SCIAMACHY on ESA’s Envisat and GOME-2 on the European Meteorological Satellite Organization’s MetOp-A."We found a global slightly positive trend of ozone increase of almost 1% per decade in the total ozone from the last 14 years: a result that was confirmed by comparisons with ground-based measurements," said Diego G. Loyola R. who worked on the project with colleagues from the German Aerospace Center (DLR).Ozone is a protective layer found about 25 km above us mostly in the stratospheric layer of the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. The thinning of this layer increases the risk of skin cancer, cataracts and harm to marine life.The ozone layer is not distributed evenly, with more changes occurring in the upper stratosphere. By collecting data while looking sideways (limb viewing) rather than vertically downwards, instruments are able to provide highly accurate measurements of the stratosphere.A team of scientists around Ashley Jones and Jo Urban from Sweden’s Chalmers University of Technology combined the limb measurements of US instruments SBUV, SAGE I+II and HALOE with data from OSIRIS, SMR and SCIAMACHY on the European satellites Odin and Envisat to analyse the long-term evolution of stratospheric ozone from 1979 to the present. These data show a decrease in ozone from 1979 until 1997, and a small increase since then."Our analysis shows that upper stratospheric ozone declines at northern and southern mid-latitudes at roughly 7% per decade during 1979–97, consistent with earlier studies based on data from satellites and ground networks. A clear statistically significant change of trend can be seen around 1997. The small increase (of 0.8–1.4% per decade) observed thereafter, from 1997 to 2008, is however not yet statistically different from a zero trend. We hope to see a significant recovery of (upper stratospheric) ozone in the next years using longer, extended satellite time-series," Urban said.The thinning of the ozone layer is caused by chemicals such as human-produced bromine and chlorine gases that have long lifetimes in the atmosphere. The Montreal Protocol (1987) was introduced to regulate and phase out the production of these substances. Its effect can clearly be seen in the satellite observations of ozone and these chemicals.Using SCIAMACHY data in limb-viewing observation mode from 2002 to 2008, François Hendrick from the Belgian Institute for Space Aeronomy (BIRA/IASB) and his colleagues from the University of Bremen performed a trend analysis of bromine monoxide (BrO) in the stratosphere. BrO is a highly efficient catalyst in ozone destruction. The results show a negative trend in BrO abundance in the stratosphere during this period, marking the first time a decline in stratospheric bromine has been reported from a spaceborne observation."The good agreement with ground-based observations at high and mid-latitudes show that SCIAMACHY limb data can be used for stratospheric BrO trend monitoring. These findings provide strong evidences that the Montreal Protocol restrictions on brominated substances have now reached the stratosphere," Hendrick said.Having access to these atmospheric satellite data over long periods is important for scientists to identify and analyse long-term trends and changes. In addition to monitoring ozone trends, scientists will continue to monitor ozone-depleting substances that were phased out under the Montreal Protocol but continue to linger in the atmosphere.All of these results were presented at ESA’s five-day ‘Atmospheric Science Conference’ held in Barcelona, Spain, 7–11 September. The objective of the conference was to provide scientists and researchers with the opportunity to present up-to-date results from their atmospheric research and application projects using space-based atmospheric sensors.

Ozone Holes

September 16, 2009

https://www.sciencedaily.com/releases/2009/09/090915113534.htm

Changes In Earth's Ozone Layer Predicted To Increase UV Radiation In Tropics And Antarctica

Physicists at the University of Toronto have discovered that changes in the Earth’s ozone layer due to climate change will reduce the amount of ultraviolet (UV) radiation in northern high latitude regions such as Siberia, Scandinavia and northern Canada. Other regions of the Earth, such as the tropics and Antarctica, will instead face increasing levels of UV radiation.

“Climate change is an established fact, but scientists are only just beginning to understand its regional manifestations,” says Michaela Hegglin, a postdoctoral fellow in the Department of Physics, and the lead author of the study published in Using a sophisticated computer model, Hegglin and U of T physicist Theodore Shepherd determined that 21st-century climate change will alter atmospheric circulation, increasing the flux of ozone from the upper to the lower atmosphere and shifting the distribution of ozone within the upper atmosphere. The result will be a change in the amount of UV radiation reaching the Earth’s surface which varies dramatically between regions: e.g. up to a 20 per cent increase in UV radiation over southern high latitudes during spring and summer, and a nine per cent decrease in UV radiation over northern high latitudes, by the end of the century.While the effects of increased UV have been widely studied because of the problem of ozone depletion, decreased UV could have adverse effects too, e.g. on vitamin D production for people in regions with limited sunlight such as the northern high latitudes.“Both human and ecosystem health are affected by air quality and by UV radiation,” says Shepherd. “While there has been much research on the impact of climate change on air quality, our work shows that this research needs to include the effect of changes in stratospheric ozone. And while there has been much research on the impact of ozone depletion on UV radiation and its impacts on human and ecosystem health, the notion that climate change could also affect UV radiation has not previously been considered. This adds to the list of potential impacts of climate change, and is especially important for Canada as northern high latitudes are particularly affected.”The research was funded by the Canadian Foundation for Climate and Atmospheric Sciences through the C-SPARC project. The C-SPARC project is a national collaboration between Environment Canada and several Canadian universities.

Ozone Holes

August 28, 2009

https://www.sciencedaily.com/releases/2009/08/090827141349.htm

Small Fluctuations In Solar Activity, Large Influence On Climate

Subtle connections between the 11-year solar cycle, the stratosphere, and the tropical Pacific Ocean work in sync to generate periodic weather patterns that affect much of the globe, according to research appearing this week in the journal

An international team of scientists led by the National Center for Atmospheric Research (NCAR) used more than a century of weather observations and three powerful computer models to tackle one of the more difficult questions in meteorology: if the total energy that reaches Earth from the Sun varies by only 0.1 percent across the approximately 11-year solar cycle, how can such a small variation drive major changes in weather patterns on Earth?The answer, according to the new study, has to do with the Sun's impact on two seemingly unrelated regions. Chemicals in the stratosphere and sea surface temperatures in the Pacific Ocean respond during solar maximum in a way that amplifies the Sun's influence on some aspects of air movement. This can intensify winds and rainfall, change sea surface temperatures and cloud cover over certain tropical and subtropical regions, and ultimately influence global weather."The Sun, the stratosphere, and the oceans are connected in ways that can influence events such as winter rainfall in North America," says NCAR scientist Gerald Meehl, the lead author. "Understanding the role of the solar cycle can provide added insight as scientists work toward predicting regional weather patterns for the next couple of decades."The study was funded by the National Science Foundation, NCAR's sponsor, and by the Department of Energy. It builds on several recent papers by Meehl and colleagues exploring the link between the peaks in the solar cycle and events on Earth that resemble some aspects of La Nina events, but are distinct from them. The larger amplitude La Nina and El Nino patterns are associated with changes in surface pressure that together are known as the Southern Oscillation.The connection between peaks in solar energy and cooler water in the equatorial Pacific was first discovered by Harry Van Loon of NCAR and Colorado Research Associates, who is a co-author of the new paper.The new contribution by Meehl and his colleagues establishes how two mechanisms that physically connect changes in solar output to fluctuations in the Earth's climate can work together to amplify the response in the tropical Pacific.The team first confirmed a theory that the slight increase in solar energy during the peak production of sunspots is absorbed by stratospheric ozone. The energy warms the air in the stratosphere over the tropics, where sunlight is most intense, while also stimulating the production of additional ozone there that absorbs even more solar energy. Since the stratosphere warms unevenly, with the most pronounced warming occurring at lower latitudes, stratospheric winds are altered and, through a chain of interconnected processes, end up strengthening tropical precipitation.At the same time, the increased sunlight at solar maximum causes a slight warming of ocean surface waters across the subtropical Pacific, where Sun-blocking clouds are normally scarce. That small amount of extra heat leads to more evaporation, producing additional water vapor. In turn, the moisture is carried by trade winds to the normally rainy areas of the western tropical Pacific, fueling heavier rains and reinforcing the effects of the stratospheric mechanism.The top-down influence of the stratosphere and the bottom-up influence of the ocean work together to intensify this loop and strengthen the trade winds. As more sunshine hits drier areas, these changes reinforce each other, leading to less clouds in the subtropics, allowing even more sunlight to reach the surface, and producing a positive feedback loop that further magnifies the climate response.These stratospheric and ocean responses during solar maximum keep the equatorial eastern Pacific even cooler and drier than usual, producing conditions similar to a La Nina event. However, the cooling of about 1-2 degrees Fahrenheit is focused farther east than in a typical La Nina, is only about half as strong, and is associated with different wind patterns in the stratosphere.Earth's response to the solar cycle continues for a year or two following peak sunspot activity. The La Nina-like pattern triggered by the solar maximum tends to evolve into a pattern similar to El Nino as slow-moving currents replace the cool water over the eastern tropical Pacific with warmer water. The ocean response is only about half as strong as with El Nino and the lagged warmth is not as consistent as the La Nina-like pattern that occurs during peaks in the solar cycle.Solar maximum could potentially enhance a true La Nina event or dampen a true El Nino event. The La Nina of 1988-89 occurred near the peak of solar maximum. That La Nina became unusually strong and was associated with significant changes in weather patterns, such as an unusually mild and dry winter in the southwestern United States.The Indian monsoon, Pacific sea surface temperatures and precipitation, and other regional climate patterns are largely driven by rising and sinking air in Earth's tropics and subtropics. Therefore the new study could help scientists use solar-cycle predictions to estimate how that circulation, and the regional climate patterns related to it, might vary over the next decade or two.To tease out the elusive mechanisms that connect the Sun and Earth, the study team needed three computer models that provided overlapping views of the climate system.One model, which analyzed the interactions between sea surface temperatures and lower atmosphere, produced a small cooling in the equatorial Pacific during solar maximum years. The second model, which simulated the stratospheric ozone response mechanism, produced some increases in tropical precipitation but on a much smaller scale than the observed patterns.The third model contained ocean-atmosphere interactions as well as ozone. It showed, for the first time, that the two combined to produce a response in the tropical Pacific during peak solar years that was close to actual observations."With the help of increased computing power and improved models, as well as observational discoveries, we are uncovering more of how the mechanisms combine to connect solar variability to our weather and climate," Meehl says.The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation.

Ozone Holes

August 28, 2009

https://www.sciencedaily.com/releases/2009/08/090827141344.htm

Nitrous Oxide Now Top Ozone-depleting Emission

Nitrous oxide has now become the largest ozone-depleting substance emitted through human activities, and is expected to remain the largest throughout the 21st century, NOAA scientists say in a new study.

For the first time, this study has evaluated nitrous oxide emissions from human activities in terms of their potential impact on Earth's ozone layer. As chlorofluorocarbons (CFCs), which have been phased out by international agreement, ebb in the atmosphere, nitrous oxide will remain a significant ozone-destroyer, the study found. Today, nitrous oxide emissions from human activities are more than twice as high as the next leading ozone-depleting gas.Nitrous oxide is emitted from natural sources and as a byproduct of agricultural fertilization and other industrial processes. Calculating the effect on the ozone layer now and in the future, NOAA researchers found that emissions of nitrous oxide from human activities erode the ozone layer and will continue to do so for many decades.The study, authored by A.R. Ravishankara, J.S. Daniel and Robert W. Portmann of the NOAA Earth System Research Laboratory (ESRL) chemical sciences division, appears online today in the journal Science. ESRL tracks the thickness of the ozone layer, as well as the burden of ozone-depleting compounds in the atmosphere. It maintains a large portion of the world air sampling and measurement network. NOAA scientists also conduct fundamental studies of the atmosphere and atmospheric processes to improve understanding of ozone depletion and of the potential for recovery the ozone layer."The dramatic reduction in CFCs over the last 20 years is an environmental success story. But manmade nitrous oxide is now the elephant in the room among ozone-depleting substances," said Ravishankara, lead author of the study and director of the ESRL Chemical Sciences Division in Boulder, Colo.The ozone layer serves to shield plants, animals and people from excessive ultraviolet light from the sun. Thinning of the ozone layer allows more ultraviolet light to reach the Earth's surface where it can damage crops and aquatic life and harm human health.Though the role of nitrous oxide in ozone depletion has been known for several decades, the new study is the first to explicitly calculate that role using the same measures that have been applied to CFCs, halons and other chlorine- and bromine-containing ozone-depleting substances.With CFCs and certain other ozone-depleting gases coming in check as a result of the 1987 Montreal Protocol, the international treaty that phased out ozone-destroying compounds, manmade nitrous oxide is becoming an increasingly larger fraction of the emissions of ozone-depleting substances. Nitrous oxide is not regulated by the Montreal Protocol.Nitrous oxide is also a greenhouse gas, so reducing its emission from manmade sources would be good for both the ozone layer and climate, the scientists said.In addition to soil fertilization, nitrous oxide is emitted from livestock manure, sewage treatment, combustion and certain other industrial processes. Dentists use it as a sedative (so-called "laughing gas"). In nature, bacteria in soil and the oceans break down nitrogen-containing compounds, releasing nitrous oxide. About one-third of global nitrous oxide emissions are from human activities. Nitrous oxide, like CFCs, is stable when emitted at ground level, but breaks down when it reaches the stratosphere to form other gases, called nitrogen oxides, that trigger ozone-destroying reactions.

Ozone Holes

August 27, 2009

https://www.sciencedaily.com/releases/2009/08/090826110110.htm

New Technology Cuts Industrial Odors, Pollutants

A North Carolina State University researcher has devised a new technology that really does not stink. In fact, it could be the key to eliminating foul odors and air pollutants emitted by industrial chicken rendering facilities and – ultimately – large-scale swine feedlots.

Dr. Praveen Kolar, assistant professor of biological and agricultural engineering at NC State, has developed an inexpensive treatment process that significantly mitigates odors from poultry rendering operations. Rendering facilities take animal byproducts (e.g., skin, bones, feathers) and process them into useful products such as fertilizer. However, the rendering process produces extremely foul odors.These emissions are not currently regulated by the government, but the smell can be extremely disruptive to a facility's community. The industry currently uses chemical "scrubbers" to remove odor-causing agents, but this technique is not very effective, Kolar says. Furthermore, some of the odor-causing compounds are aldehydes, which can combine with other atmospheric compounds to form ozone – triggering asthma attacks and causing other adverse respiratory health effects.Kolar, working with his co-author Dr. James Kastner at the University of Georgia, has designed an effective filtration system that takes advantage of catalytic oxidation to remove these odor-causing pollutants. Specifically, the researchers use ozone and specially-designed catalysts to break down the odor-causing compounds. This process takes place at room temperature, so there are no energy costs, and results in only two byproducts: carbon dioxide and pure water.The researchers developed the catalysts by coating structures made of activated carbon with a nanoscale film made of cobalt or nickel oxides, Kolar says. "We used activated carbon because its porous structure gives it an extremely large surface area," Kolar explains, "meaning that there is more area that can be exposed to the odorous agents." The cobalt and nickel oxide nanofilms make excellent catalysts, Kolar explains, "because they increase the rate of the chemical reaction between the odor-causing compounds and the ozone, making the process more efficient. They are also metals that are both readily available and relatively inexpensive."Kolar says his next goal is to apply this research to industrial hog farms. "This technology could be applied to swine operations to address odors and ammonia emissions," Kolar says. "My next step is to try to pursue this research on a large scale."

Ozone Holes

August 18, 2009

https://www.sciencedaily.com/releases/2009/08/090818130425.htm

Ancient Climate: The Greenhouse Gas That Saved The World

When Planet Earth was just cooling down from its fiery creation, the sun was faint and young. So faint that it should not have been able to keep the oceans of earth from freezing. But fortunately for the creation of life, water was kept liquid on our young planet. For years scientists have debated what could have kept earth warm enough to prevent the oceans from freezing solid.

Now a team of researchers from Tokyo Institute of Technology and University of Copenhagen's Department of Chemistry have coaxed an explanation out of ancient rocks, as reported in this week's issue of "The young sun was approximately 30 percent weaker than it is now, and the only way to prevent earth from turning into a massive snowball was a healthy helping of greenhouse gas," Associate Professor Matthew S. Johnson of the Department of Chemistry explains. And he has found the most likely candidate for an archean atmospheric blanket. Carbonyl Sulphide: A product of the sulphur disgorged during millennia of volcanic activity."Carbonyl Sulphide is and was the perfect greenhouse gas. Much better than Carbon Dioxide. We estimate that a blanket of Carbonyl Sulphate would have provided about 30 percent extra energy to the surface of the planet. And that would have compensated for what was lacking from the sun," says Professor Johnson.To discover what could have helped the faint young sun warm early earth, Professor Johnson and his colleagues in Tokyo examined the ratio of sulphur isotopes in ancient rocks. And what they saw was a strange signal; A mix of isotopes that couldn't very well have come from geological processes."There is really no process in the rocky mantle of earth that would explain this distribution of isotopes. You would need something happening in the atmosphere," says Johnson. The question was what. Painstaking experimentation helped them find a likely atmospheric process. By irradiating sulphur dioxide with different wavelengths of sunlight, they observed that sunlight passing through Carbonyl Sulphide gave them the wavelengths that produced the weird isotope mix."Shielding by Carbonyl Sulphide is really a pretty obvious candidate once you think about it, but until we looked, everyone had missed it," says Professor Johnson, and he continues."What we found is really an archaic analogue to the current ozone layer. A layer that protects us from ultraviolet radiation. But unlike ozone, Carbonyl Sulphide would also have kept the planet warm. The only problem is: It didn't stay warm."As life emerged on earth it produced increasing amounts of oxygen. With an increasingly oxidizing atmosphere, the sulphur emitted by volcanoes was no longer converted to Carbonyl Sulphide. Instead it got converted to sulphate aerosols: A powerful climate coolant. Johnson and his co-workers created a Computer model of the ancient atmosphere. And the models in conjunction with laboratory experiments suggest that the fall in levels of Carbonyl Sulphide and rise of sulphate aerosols taken together would have been responsible for creating snowball earth, the planetwide ice-age hypothesised to have taken place near the end of the Archean eon 2500 million years ago.And the implications to Johnson are alarming: "Our research indicates that the distribution and composition of atmospheric gasses swung the planet from a state of life supporting warmth to a planet-wide ice-age spanning millions of years. I can think of no better reason to be extremely cautious about the amounts of greenhouse gasses we are currently emitting to the atmosphere."

Ozone Holes

August 10, 2009

https://www.sciencedaily.com/releases/2009/08/090806091014.htm

Looking Back At Earth: LCROSS Spacecraft Successfully Detects Life On The Blue Planet

On Saturday, Aug. 1, 2009, the LCROSS spacecraft successfully completed its first Earth-look calibration of its science payload. An additional Earth-look and a moon-look are scheduled for the remainder of the cruise phase of the mission.

The purpose of the LCROSS Earth-look was to perform a routine health check on the science instruments, refine camera exposure settings, check instrument pointing alignment, and check radiometric and wavelength calibrations.From its vantage point of 223,700 miles (360,000 km) from Earth, the LCROSS science team changing exposure and integration settings on the spacecraft's infrared cameras and spectrometers and performed a crossing pattern, pushing the smaller fields of view of the spectrometers across the Earth’s disk. At this range, the Earth was approximately 2.2 degrees in diameter."The Earth-look was very successful," said Tony Colaprete, LCROSS project scientist. "The instruments are all healthy and the science teams was able to collect additional data that will help refine our calibrations of the instruments."During the Earth observations, the spacecraft's spectrometers were able to detect the signatures of the Earth's water, ozone, methane, oxygen, carbon dioxide and possibly vegetation.

Ozone Holes

August 9, 2009

https://www.sciencedaily.com/releases/2009/08/090806141716.htm

Ozone Depletion Reduces Ocean Carbon Uptake

The Southern Ocean plays an important role in mitigating climate change because it acts as a sink of atmospheric carbon dioxide. Most current models predict that the strength of the Southern Ocean carbon dioxide sink should increase as atmospheric carbon dioxide rises, but observations show that this has not been the case.

To help resolve this discrepancy, Lenton et al. consider the effects of stratospheric ozone depletion, which most previous studies had not included. They compare coupled carbon-climate models with and without ozone depletion and find that including ozone depletion produced a significant reduction in Southern Ocean carbon uptake, in good agreement with observed trends. The simulations show that ozone depletion, combined with increased atmospheric greenhouse gas concentration, drives stronger winds above the Southern Ocean. These stronger winds bring more carbon-rich deep water to the surface, which reduces the ocean's ability to absorb more carbon dioxide from the atmosphere. The authors also find that ozone depletion increases ocean acidification. They suggest that future climate models should take stratospheric ozone into account.

Ozone Holes

August 9, 2009

https://www.sciencedaily.com/releases/2009/07/090720190728.htm

Chemists Discover Ozone-boosting Reaction: Newfound Chemistry Should Be Added To Atmospheric Models, Experts Say

Burning of fossil fuels pumps chemicals into the air that react on surfaces such as buildings and roads to create photochemical smog-forming chlorine atoms, UC Irvine scientists report in a new study.

Under extreme circumstances, this previously unknown chemistry could account for up to 40 parts per billion of ozone – nearly half of California's legal limit on outdoor air pollution. This reaction is not included in computer models used to predict air pollution levels and the effectiveness of ozone control strategies that can cost billions of dollars.Ozone can cause coughing, throat irritation, chest pain and shortness of breath. Exposure to it has been linked to asthma, bronchitis, cardiopulmonary problems and premature death."Realistically, this phenomenon probably accounts for much less than 40 parts per billion, but our results show it could be significant. We should be monitoring it and incorporating it into atmospheric models," said Barbara Finlayson-Pitts, Distinguished Professor of Chemistry and lead author of the study. "We still don't really understand important elements of the atmosphere's chemistry."When fossil fuels burn, compounds called nitrogen oxides are generated. Previously, scientists believed these would be eliminated from the atmosphere upon contact with surfaces.But UCI scientists discovered that when nitrogen oxides combine with hydrochloric acid from airborne sea salt on buildings, roads and other particles in the air, highly reactive chlorine atoms are created that speed up smog formation.Hydrochloric acid also is found indoors in cleaning products. When it interacts with nitrogen oxides from appliances such as gas stoves, chlorine compounds form that cause unusual chemistry and contribute to corrosion indoors.The study was undertaken by scientists involved with AirUCI, an Environmental Molecular Sciences Institute funded by the National Science Foundation. UCI's Jonathan Raff conducted experiments; Bosiljka Njegic and Benny Gerber made theoretical predictions; and Wayne Chang and Donald Dabdub did the modeling. Mark Gordon of Iowa State University also helped with theory.Said Finlayson-Pitts: "This is a great example of how our unique collaborative group can produce some really great science."

Ozone Holes

August 7, 2009

https://www.sciencedaily.com/releases/2009/08/090806191938.htm

More Accurate Weather Forecasts Coming Soon

More accurate global weather forecasts and a better understanding of climate change are in prospect, thanks to a breakthrough by engineers at Queen's University Belfast's Institute of Electronics, Communications and Information Technology (ECIT).

The ECIT team has developed a high performance electronic device -- known as a dual polarized Frequency Selective Surface filter -- that is to be used in future European Space Agency (ESA) missions.The filters will be installed in instruments being developed by ESA for meteorological satellites it plans to launch between 2018 and 2020. The ESA instruments are used to detect thermal emissions in the Earth's atmosphere. The data measures temperature, humidity profiles, and gas composition, which are in turn entered into operational systems and used to forecast weather and pollution.Lead ECIT engineer Raymond Dickie said: "Measuring just 30mm in diameter and 1/100mm thick, the devices will help to provide a much more comprehensive analysis of conditions in the Earth's atmosphere than has been possible previously."Up to now, spaceborne remote sensing instruments have only been capable of separating either the vertically or horizontally polarized components of naturally occurring thermal emissions from gases in the Earth's atmosphere - but not both together at the same time. The invention of the new filter resolves this problem and will enable complex imaging of clouds to be undertaken for the first time at very short wavelengths."Global patent applications have already been filed for the filters which are constructed by ECIT engineers and research staff at Queen's University's Northern Ireland Semiconductor Research Centre in Belfast. The filters have been developed as a result of a £1.2 million investment in Queen's by EPSRC, EADS Astrium and ESA to develop the technology, and have taken over 10 years to develop.Robert Cahill, a member of the project team added: "As a result of the new filter, scientists will gain access to completely new data on a range of phenomenon including ozone depletion and the size of water particles in cirrus clouds. This in turn will enable more accurate global weather forecasts to be compiled and will provide important new insights into climate change."

Ozone Holes

August 7, 2009

https://www.sciencedaily.com/releases/2009/08/090806080142.htm

Geoengineering To Mitigate Global Warming May Cause Other Environmental Harm

Geoengineering techniques aim to slow global warming through the use of human-made changes to the Earth's land, seas or atmosphere. But new research shows that the use of geoengineering to do environmental good may cause other environmental harm. In a symposium at the Ecological Society of America's Annual Meeting, ecologists discuss the viability of geoengineering, concluding that it is potentially dangerous at the global scale, where the risks outweigh the benefits.

"The bigger the scale of the approach, the riskier it is for the environment," says session organizer Robert Jackson , director of Duke University's Center on Global Change. Global alterations of Earth's natural cycles have too many uncertainties to be viable with our current level of understanding, he says.One global-scale geoengineering method, termed atmospheric seeding, would cool the climate by releasing light-colored sulfur particles or other aerosols into the atmosphere to reflect the sun's rays back into space. This approach mimics what happens naturally when volcanoes erupt; in 1991, for instance, an eruption of Mount Pinatubo in the Philippines cooled the Earth by 0.9 degrees Fahrenheit.But Simone Tilmes of the National Center for Atmospheric Research argues that despite its potential to create overall cooling, atmospheric seeding could cause significant changes in localized temperature and precipitation. Her simulations also predict that sulfur seeding could destroy atmospheric ozone, leading to increased ultraviolet radiation reaching the Earth's surface."An increase in ozone depletion over the Arctic could lead to dangerous levels of ultraviolet light hitting the Earth's surface," she says. "In this case, the recovery of the ozone hole over the Antarctic could be delayed by decades."Another large-scale geoengineering scheme is fertilizing the oceans with iron to increase carbon uptake from the atmosphere. Charles Miller of Oregon State University says that ocean fertilization could create a rise in iron-limited phytoplankton populations, which by dying and sinking would use enough oxygen to create extensive dead zones in the oceans. In addition, he says, the maximum possible rate of ocean iron fertilization could only offset a small fraction of the current rate of carbon burning by humans.Ocean fertilization also does not alleviate the increasing problem of ocean acidification, caused by carbon dioxide from the increasingly carbon-rich atmosphere dissolving into seawater. In fact, Miller says, ocean fertilization schemes will likely exacerbate this problem."Any large-scale fertilization could cause risks to ocean ecosystems as great as those of global warming itself," he says.Despite its apparent hazards at the global scale, Jackson thinks that research should continue on safer ways to use geoengineering at a smaller scale. Geologic sequestration, sometimes known as CO2 capture and storage, takes CO2 out of the atmosphere and stores it in underground reservoirs. Jackson says that this solution has the potential to store more than a century's worth of electric power emissions at a relatively low cost. He notes, however, that some potential risks of geologic sequestration include carbon leakage and the potential for interactions with groundwater.But on the planetary scale, most ecologists are skeptical of climate engineering."Playing with the Earth's climate is a dangerous game with unclear rules," says Jackson. "We need more direct ways to tackle global warming, including energy efficiency, reduced consumption, and investment in renewable energy sources."Clifford Duke, Director of Science Programs at the Ecological Society of America, is co-organizer of the symposium. Additional speakers include David Keith from the University of Calgary and Phillip Duffy from Climate Central, Inc.The researchers will present their results in "Symposium 21 - The Environmental Effects of Geoengineering" on August 6, 2009 in the Albuquerque Convention Center.

Ozone Holes

July 24, 2009

https://www.sciencedaily.com/releases/2009/07/090723175500.htm

Even Healthy Lungs Labor At Acceptable Ozone Levels

Ozone exposure, even at levels deemed safe by current clean air standards, can have a significant and negative effect on lung function, according to researchers at the University of California Davis.

"The National Ambient Air Quality Standard (NAAQS) for ozone was recently revised to set lower limits for ozone concentrations. Our research indicates that the threshold for decrements in ozone-induced lung function in healthy young subjects is below this standard," said Edward Schelegle, Ph.D., of the University of California Davis. "Specifically, we found that 6.6 hours exposure to mean ozone concentrations as low as 70 parts per billion have a significant negative effect on lung function, even though the current NAAQS standards allow ozone concentrations to be up to 75 parts per billion (ppb) over an eight-hour period."The results we published in the August 1 issue of the American Thoracic Society's American To test whether mean ozone concentrations above and below the new standard induce lung function decrements and to further study the time-course of these decrements, Dr. Schelegle and colleagues recruited 31 healthy nonsmoking individuals to participate in 6.6-hour sessions during which they were exposed to ozone at 60, 70, 80 or 87 ppb or filtered air while undergoing six 50-minute bouts of moderate exercise followed by 10-minute breaks. A 35-minute lunch break separated the third and fourth bouts of exercise.Lung function for each subject was assessed before, during and after exposure, and each individual answered a questionnaire evaluating their subjective symptoms. Of the four levels of ozone concentration tested, Dr. Schelegle and colleagues found significant decrements in both lung function and subjective respiratory symptoms at 70 ppb and above, beginning at 5.6 hours after exposure."These data tells us that even at levels currently below the air quality standard, healthy people may experience decreased lung function after just a few hours of moderate to light exercise such as bicycling or walking," said Dr. Schelegle. "While these changes were fully reversible within several hours, these findings highlight the need to study susceptible individuals, such as asthmatics, at similar ozone concentrations and durations of exposure. These studies are needed to better understand the acute rise in hospitalizations that often occur in conjunction with high-ozone periods."The study also supports the previously reported smooth dose-response curve associated with ozone. That is, the higher the level of ozone, the greater the decrease in lung function. However, the healthy subjects in the study showed a marked individual variability in their responses to ozone, with a few exhibiting strong sensitivity to ozone concentrations. What causes some individuals to respond strongly while others do not is still unknown."Schelegle and colleagues do not, nor did they seek to explain the determinants of susceptibility in young, healthy adults," noted James S. Brown, of the U.S. Environmental Protection Agency, in an accompanying editorial. "Only with continued research efforts will we be able to better characterize the susceptibility in some healthy individuals, to the effects of short-term ozone exposures."Dr. Schelegle also notes the need for further research to further elucidate the precise mechanisms that determine an individual's ozone responsiveness in both healthy and susceptible populations. "Understanding how these mechanisms change with repeated daily exposures is critical, especially as ambient ozone levels are often elevated several days in a row," Dr. Schelegle said.

Ozone Holes

July 10, 2009

https://www.sciencedaily.com/releases/2009/07/090709120657.htm

Ozone, Nitrogen Change The Way Rising Carbon Dioxide Affects Earth's Water

Through a recent modeling experiment, a team of NASA-funded researchers have found that future concentrations of carbon dioxide and ozone in the atmosphere and of nitrogen in the soil are likely to have an important but overlooked effect on the cycling of water from sky to land to waterways.

The researchers concluded that models of climate change may be underestimating how much water is likely to run off the land and back into the sea as atmospheric chemistry changes. Runoff may be as much as 17 percent higher in forests of the eastern United States when models account for changes in soil nitrogen levels and atmospheric ozone exposure."Failure to consider the effects of nitrogen limitation and ozone on photosynthesis can lead us to underestimate regional runoff," said Benjamin Felzer, an ecosystem modeler at Lehigh University in Bethlehem, Pa. "More runoff could mean more contamination and flooding of our waterways. It could also mean fewer droughts than predicted for some areas and more water available for human consumption and farming. Either way, water resource managers need more accurate runoff estimates to plan better for the changes."Felzer and colleagues from the Massachusetts Institute of Technology (MIT) in Cambridge and the Marine Biology Laboratory in Woods Hole, Mass., published their findings recently in the Journal of Geophysical Research – Biogeosciences.Plants play a significant role in Earth's water cycle, regulating the amount of water cycling through land ecosystems and how long it stays there. Plants draw in water from the atmosphere and soil, and they discharge it naturally through transpiration, the tail end of photosynthesis when water vapor and oxygen are released into the air.The amount of water that plants give up depends on how much carbon dioxide is present in the atmosphere. Studies have shown that despite a global drop in rainfall over land in the past 50 years, runoff has actually increased.Other studies have shown that increasing COPlants that release less water also take less of it from the environment. With less water being taken up by plants, more water is available for groundwater or runs off the land surface into lakes, streams, and rivers. Along the way, it accumulates excess nutrients and pollutants before emptying into waterways, where it affects the health of fish, algae, and shellfish and contaminate drinking water and beaches. Excess runoff can also contribute to flooding.Sometimes rising COAware of these cycles, Felzer and colleagues used theoretical models to project various future scenarios for the amount of carbon dioxide in the atmosphere and what it would mean to the changing water cycle in forests east of the Mississippi River. They found that runoff would increase anywhere from 3 to 6 percent depending on location and the amount of the increase in COFelzer and colleagues also examined the role of two other variables -- atmospheric ozone and soil-based nitrogen -- in the changing water cycle. Excess ground-level ozone harms the cells responsible for photosynthesis. Reductions in photosynthesis leads to less transpiration and cycling of water through leaves and more water added to runoff.In most boreal and temperate forests, the rate of photosynthesis is also limited by the availability of nutrients such as nitrogen in the soil. The less nitrogen in the soil, the slower their rate of photosynthesis and transpiration."The increase in runoff is even larger when nitrogen is limited and environments are exposed to high ozone levels," said Felzer. In fact, the team found an additional 7 to 10 percent rise in runoff when nitrogen was limited and ozone exposure increased."Though this study focuses on Eastern U.S. forests, we know nitrogen and ozone effects are also important in South America and Europe. One region has seen a net increase and the other a net runoff reduction," said co-author Adam Schlosser of the Center for Global Change Science at MIT. "Our environment and quality of life depend on less uncertainty on this front."

Ozone Holes

July 9, 2009

https://www.sciencedaily.com/releases/2009/06/090622171503.htm

Beyond Carbon Dioxide: Growing Importance Of Hydrofluorocarbons (HFCs) In Climate Warming

Some of the substances that are helping to avert the destruction of the ozone layer could increasingly contribute to climate warming, according to scientists from NOAA's Earth System Research Laboratory and their colleagues in a new study in the journal

The authors took a fresh look at how the global use of hydrofluorocarbons (HFCs) is expected to grow in coming decades. Using updated usage estimates and looking farther ahead than past projections (to the year 2050), they found that HFCs—especially from developing countries—will become an increasingly larger factor in future climate warming."HFCs are good for protecting the ozone layer, but they are not climate friendly," said David W. Fahey, a scientist at NOAA and second author of the new study. "Our research shows that their effect on climate could become significantly larger than we expected, if we continue along a business-as-usual path."HFCs currently have a climate change contribution that is small (less than 1 percent) in comparison to the contribution of carbon dioxide (COHFCs, which do not contain ozone-destroying chlorine or bromine atoms, are used as substitutes for ozone-depleting compounds such as chlorofluorocarbons (CFCs) in such uses as refrigeration, air conditioning, and the production of insulating foams. The Montreal Protocol, a 1987 international agreement, has gradually phased out the use of CFCs and other ozone-depleting substances, leading to the development of long-term replacements such as HFCs.Though the HFCs do not deplete the ozone layer, they are potent greenhouse gases. Molecule for molecule, all HFCs are more potent warming agents than COThe new study factored in the expected growth in demand for air conditioning, refrigerants, and other technology in developed and developing countries. The Montreal Protocol's gradual phasing out of the consumption of ozone-depleting substances in developing countries after 2012, along with the complete phase-out in developed countries in 2020, are other factors that will lead to increased usage of HFCs and other alternatives.Decision-makers in Europe and the United States have begun to consider possible steps to limit the potential climate consequences of HFCs. The PNAS study examined several hypothetical scenarios to mitigate HFC consumption. For example, a global consumption limit followed by a 4 percent annual reduction would cause HFC-induced climate forcing to peak in the year 2040 and then begin to decrease before the year 2050."While unrestrained growth of HFC use could lead to significant climate implications by 2050, we have shown some examples of global limits that can effectively reduce the HFCs' impact," said John S. Daniel, a NOAA coauthor of the study.The authors of the PNAS study are Guus J.M Velders of the Netherlands Environmental Assessment Agency, Fahey and Daniel of NOAA's Earth System Research Laboratory, Mack McFarland of DuPont Fluoroproducts, and Stephen O. Andersen of the U.S. Environmental Protection Agency.

Ozone Holes

June 24, 2009

https://www.sciencedaily.com/releases/2009/06/090624093458.htm

Ozone Hole Reduces Atmospheric Carbon Dioxide Uptake In Southern Ocean

Does ozone have an impact on the ocean's role as a "carbon sink"? Yes, according to researchers from three laboratories

These results, which are published online in the journal Geophysical Research Letters, should have a considerable impact on future models of the IPCCThe increase in COIn order to improve these simulations, a collaborative team of climatologists, modelers and oceanographers was set up. Their objective: to develop a model that more accurately simulates the Southern Ocean's ability to act as a carbon sink. To do this, the researchers based their studies on the IPSL's coupled ocean/atmosphere model, which integrates the carbon cycle (and thus the evolution of greenhouse gases, such as COAbove all, this study highlights two major phenomena with regard to the Southern Ocean: a significant reduction in COThis is the first time that the impact of the ozone hole on the oceanic carbon cycle has been simulated in a global climate model. These results suggest that the climate models used until now have overestimated oceanic carbon uptake and underestimated ocean acidification. They underline the importance of taking ozone into account in future modeling, particularly by the IPCC, which will make it possible to improve future climate predictions. The Southern Ocean is a region that is particularly sensitive to global warming.Predicting the consequences of such changes more accurately is fundamental, not just with regard to the global carbon balance (saturation of air-sea fluxes) but also marine resources (impact of acidification).This work was supported by the National LEFE/Cyber/FlamenCO(1) Grouped together within the Institut Pierre-Simon Laplace (IPSL), the three laboratories concerned are: the Laboratoire d'Océanographie et du Climat: Expérimentations et Approches Numériques (LOCEAN, UPMC/CNRS/MNHN/IRD), the Laboratoire de Météorologie Dynamique (LMD, UPMC/CNRS/ENS Paris/Ecole Polytechnique) and the Laboratoire des Sciences du Climat et de l'Environnement (LSCE, UVSQ/CNRS/CEA).(2) Institut National des Sciences de l'Univers of the CNRS.(3) IPCC - Intergovernmental Panel on Climate Change.(4) The stratosphere is the second major layer of the Earth's atmosphere, situated between about 6 and 30 miles altitude. It contains the famous "ozone layer".(5) OISO - Indian Ocean Observation Service, created around ten years ago thanks to the support, in France, of INSU-CNRS, IPEV and IPSL.

Ozone Holes

May 11, 2009

https://www.sciencedaily.com/releases/2009/05/090504205108.htm

Future Climate Change Likely To Cause More Respiratory Problems In Young Children

More children will end up hospitalized over the next decade because of respiratory problems as a result of projected climate change, according to a new study from Mount Sinai School of Medicine.

The lead author of this research is Perry Elizabeth Sheffield, MD, Pediatric Environmental Health Fellow in the Department of Community and Preventive Medicine and the Department of Pediatrics at Mount Sinai School of Medicine.* Mount Sinai worked with Natural Resources Defense Council and the Columbia University Mailman School of Public Health on this eye-opening research that finds a direct connection between air pollution and the health of children.Ozone has many known negative respiratory health effects to which children are particularly vulnerable. An important projected consequence of climate change is the increase in ground-level ozone. Urban areas such as the New York City metropolitan area are at a higher risk of increasing temperature compared to rural areas. However, while more ozone is formed in higher temperatures, the downwind suburban areas are predicted in some of the models to experience higher ozone levels.For this study, Dr. Sheffield and her colleagues created a model describing future projected rates of respiratory hospitalizations for children less than two years of age using baseline NYC metropolitan area hospitalization rates from publicly available corresponding state Department of Health databases. These hospitalization rates were then compared to a previously developed dose-response relationship between ozone levels and pediatric respiratory hospitalizations, and the expected New York City eight-hour daily maximum ozone levels for the 2020s, as projected by a regional climate model created by the NY Climate and Health Project, supported by a grant from the US Environmental Protection Agency. Two separate future scenarios were used. The two scenarios differed by the amount of projected ozone precursor emissions (chemicals that are converted to ozone by light and heat).In both scenarios, ozone levels rise by 2020. The study found that by 2020, respiratory hospitalizations are projected to rise between four and seven percent for children under two years old because of projected air pollution (ozone) increases. The scenario with increased ozone precursors showed less of an overall increase in hospital admissions because of a paradoxical reduction in ozone due to the effects of air pollutant interactions, sometimes referred to as the scavenger molecule effect. These are likely conservative estimates because population was held constant, a single dose response function was used for the entire area, and most counties were not weighted by race and ethnicity.“These significant changes in children's hospitalizations from respiratory illnesses would be a direct result of projected climate-change effects on ground-level ozone concentrations,” said Dr. Sheffield. “This research is important because it shows that we as a country need to implement policies that both improve air quality and also prevent climate change because this could improve health in the present and prevent worsening respiratory illness in the future.”“Our study supports the necessity of improving air pollution around the world. We need to begin to make these improvements through industry emission controls, traffic reduction policies, and increased enforcement of traffic regulations,” said study co-author Dr. Philip Landrigan, Professor and Chair of Community and Preventive Medicine, and Director of the Children's Environmental Health Center, at Mount Sinai School of Medicine.*The abstract was presented on May 3, 2009 at the Pediatric Academic Societies Annual Meeting in Baltimore, Maryland.

Ozone Holes

May 7, 2009

https://www.sciencedaily.com/releases/2009/05/090507094218.htm

Rise Of Oxygen Caused Earth's Earliest Ice Age

Geologists may have uncovered the answer to an age-old question - an ice-age-old question, that is. It appears that Earth's earliest ice ages may have been due to the rise of oxygen in Earth's atmosphere, which consumed atmospheric greenhouse gases and chilled the earth.

Alan J. Kaufman, professor of geology at the University of Maryland, Maryland geology colleague James Farquhar, and a team of scientists from Germany, South Africa, Canada, and the U.S.A., uncovered evidence that the oxygenation of Earth's atmosphere - generally known as the Great Oxygenation Event - coincided with the first widespread ice age on the planet."We can now put our hands on the rock library that preserves evidence of irreversible atmospheric change," said Kaufman. "This singular event had a profound effect on the climate, and also on life."Using sulfur isotopes to determine the oxygen content of ~2.3 billion year-old rocks in the Transvaal Supergroup in South Africa, they found evidence of a sudden increase in atmospheric oxygen that broadly coincided with physical evidence of glacial debris, and geochemical evidence of a new world-order for the carbon cycle."The sulfur isotope change we recorded coincided with the first known anomaly in the carbon cycle. This may have resulted from the diversification of photosynthetic life that produced the oxygen that changed the atmosphere," Kaufman said.Two and a half billion years ago, before the Earth's atmosphere contained appreciable oxygen, photosynthetic bacteria gave off oxygen that first likely oxygenated the surface of the ocean, and only later the atmosphere. The first formed oxygen reacted with iron in the oceans, creating iron oxides that settled to the ocean floor in sediments called banded iron-formations - layered deposits of red-brown rock that accumulated in ocean basins around the worldwide. Later, once the iron was used up, oxygen escaped from the oceans and started filling up the atmosphere.Once oxygen made it into the atmosphere, Kaufman's team suggests that it reacted with methane, a powerful greenhouse gas, to form carbon dioxide, which is 62 times less effective at warming the surface of the planet. "With less warming potential, surface temperatures may have plummeted, resulting in globe-encompassing glaciers and sea ice" said Kaufman.In addition to its affect on climate, the rise in oxygen stimulated the rise in stratospheric ozone, our global sunscreen. This gas layer, which lies between 12 and 30 miles above the surface, decreased the amount of damaging ultraviolet sunrays reaching the oceans, allowing photosynthetic organisms that previously lived deeper down, to move up to the surface, and hence increase their output of oxygen, further building up stratospheric ozone."New oxygen in the atmosphere would also have stimulated weathering processes, delivering more nutrients to the seas, and may have also pushed biological evolution towards eukaryotes, which require free oxygen for important biosynthetic pathways," said Kaufman.The result of the Great Oxidation Event, according to Kaufman and his colleagues, was a complete transformation of Earth's atmosphere, of its climate, and of the life that populated its surface. The study is published in the May issue of

Ozone Holes

April 22, 2009

https://www.sciencedaily.com/releases/2009/04/090421101629.htm

Increasing Antarctic Sea Ice Extent Linked To Ozone Hole

Increased growth in Antarctic sea ice during the past 30 years is a result of changing weather patterns caused by the ozone hole, according to new research.

Reporting in the journal Sea ice plays a key role in the global environment – reflecting heat from the sun and providing a habitat for marine life. At both poles sea ice cover is at its minimum during summer. However, during the winter freeze in Antarctica this ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than a metre to several metres, the ice insulates the warm ocean from the frigid atmosphere above. Satellite images show that since the 1970s the extent of Antarctic sea ice has increased at a rate of 100,000 square kilometres a decade.The new research helps explain why observed changes in the amount of sea-ice cover are so different in both polar regions.Lead author Professor John Turner of BAS says: “Our results show the complexity of climate change across the Earth. While there is increasing evidence that the loss of sea ice in the Arctic has occurred due to human activity, in the Antarctic human influence through the ozone hole has had the reverse effect and resulted in more ice. Although the ozone hole is in many ways holding back the effects of greenhouse gas increases on the Antarctic, this will not last, as we expect ozone levels to recover by the end of the 21st Century. By then there is likely to be around one third less Antarctic sea ice.”Using satellite images of sea ice and computer models the scientists discovered that the ozone hole has strengthened surface winds around Antarctica and deepened the storms in the South Pacific area of the Southern Ocean that surrounds the continent. This resulted in greater flow of cold air over the Ross Sea (West Antarctica) leading to more ice production in this region.The satellite data reveal the variation in sea ice cover around the entire Antarctic continent. Whilst there has been a small increase of sea ice during the autumn around the coast of East Antarctica, the largest changes are observed in West Antarctica. Sea ice has been lost to the west of the Antarctic Peninsula – a region that has warmed by almost 3ºC in the past 50 years. Further west sea ice cover over the Ross Sea has increased.Turner continues: “Understanding how polar sea ice responds to global change – whether human induced or as part of a natural process – is really important if we are to make accurate predictions about the Earth’s future climate. This new research helps us solve some of the puzzle of why sea-ice is shrinking is some areas and growing in others.”Floating sea ice caps the ocean around the Antarctic and although it is mostly only 1-2 m thick, it provides effective insulation between the frigid Antarctic atmosphere and the relatively warm ocean below. The ice extent has a minimum in autumn, but by the end of the winter covers an area of 19 million square kilometres, essentially doubling the size of the continent. Instruments flown on polar orbiting satellites have been able to map the distribution and concentration of sea ice since the late 1970s and this study used a new data set of Antarctic sea ice extent created by NASA.The ozone hole was discovered by BAS scientists in the mid-1980s and found to be a result of CFCs in the stratosphere that destroyed the ozone above the continent each spring. The loss of the ozone resulted in marked cooling in the Antarctic stratosphere, which increased the winds around the continent at that level. The effects of the ozone hole propagate down through the atmosphere during the summer and autumn so that the greatest increase in surface winds over the Southern Ocean has been during the autumn. CFCs have a long lifetime in the atmosphere and despite the Montreal Protocol, which has banned the use of CFCs, there is currently no indication of a recovery of springtime ozone concentrations. However, over approximately the next half century there is expected to be a return to the pre-ozone hole concentrations of ozone.Strong winds are a major feature of the Southern Ocean with the remoteness of the Antarctic from other landmasses allowing active depressions to ring the continent. The Antarctic continent is slightly off-pole, which results in a large number of storms over the Amundsen Sea (the Amundsen Sea Low) giving average northerly winds down the Antarctic Peninsula and cold, southerly winds off the Ross Ice Shelf. The stronger winds around the continent in Autumn as a result of the ozone hole have deepened the Amundsen Sea Low, giving the positive and negative trends in sea ice over the Ross Sea and to the west of the Antarctic Peninsula respectively. Although there has been a loss of some sea ice to the west of the Antarctic Peninsula, this is negated by the larger increase of ice in the Ross Sea, giving a net increase in the amount of ice around the Antarctic.There has been contrasting climate change across the Antarctic in recent decades. The Antarctic Peninsula has warmed as much as anywhere in the Southern Hemisphere, with loss of ice shelves and changes in the terrestrial and marine biota. The warming during the summer, which has the greatest impact on the stability of the ice shelves, has been linked to the ozone hole and increasing greenhouse gases. Recent research has suggested that the warming extends into West Antarctica. In contrast, East Antarctic has shown little change or even a small cooling around the coast, which is consistent with the small increase in sea ice extent off the coast. The increase in storm activity over the South Pacific sector is also consistent with the pattern of temperature change observed, with warming down the Antarctic Peninsula in the stronger northerly flow.

Ozone Holes

April 12, 2009

https://www.sciencedaily.com/releases/2009/04/090410143811.htm

Climate Change And Atmospheric Circulation Will Make For Uneven Ozone Recovery

Earth's ozone layer should eventually recover from the unintended destruction brought on by the use of chlorofluorocarbons (CFCs) and similar ozone-depleting chemicals in the 20th century. But new research by NASA scientists suggests the ozone layer of the future is unlikely to look much like the past because greenhouse gases are changing the dynamics of the atmosphere.

Previous studies have shown that while the buildup of greenhouse gases makes it warmer in troposphere – the level of atmosphere from Earth's surface up to 10 kilometers (6 miles) altitude – it actually cools the upper stratosphere – between 30 to 50 kilometers high (18 to 31 miles). This cooling slows the chemical reactions that deplete ozone in the upper stratosphere and allows natural ozone production in that region to outpace destruction by CFCs.But the accumulation of greenhouse gases also changes the circulation of stratospheric air masses from the tropics to the poles, NASA scientists note. In Earth's middle latitudes, that means ozone is likely to "over-recover," growing to concentrations higher than they were before the mass production of CFCs. In the tropics, stratospheric circulation changes could prevent the ozone layer from fully recovering."Most studies of ozone and global change have focused on cooling in the upper stratosphere," said Feng Li, an atmospheric scientist at the Goddard Earth Sciences and Technology Center at the University of Maryland Baltimore County, Baltimore, Md. and lead author of the study. "But we find circulation is just as important. It's not one process or the other, but both."The findings are based on a detailed computer model that includes atmospheric chemical effects, wind changes, and solar radiation changes. Li's experiment is part of an ongoing international effort organized by the United Nations Environment Programme's Scientific Assessment Panel to assess the state of the ozone layer. Li and colleagues published their analysis in March in the journal Working with Richard Stolarski and Paul Newman of NASA's Goddard Space Flight Center, Greenbelt, Md., Li adapted the Goddard Earth Observing System Chemistry-Climate Model (GEOS-CCM) to examine how climate change will affect ozone recovery. The team inserted past measurements and future projections of ozone-depleting substances and greenhouse gases into the model. Then the model projected how ozone, the overall chemistry, and the dynamics of the stratosphere would change through the year 2100."In the real world, we have observed statistically significant turnaround in ozone depletion, which can be attributed to the banning of ozone-depleting substances," said Richard Stolarski, an atmospheric chemist at Goddard and a co-author of the study. "But making that connection is complicated by the response of ozone to greenhouse gases."The researchers found that greenhouse gases alter a natural circulation pattern that influences ozone distribution. Brewer-Dobson circulation is like a pump to the stratosphere, moving ozone from the lower parts of the atmosphere, into the upper stratosphere over the tropics. Air masses then flow north or south through the stratosphere, away from the tropics toward the poles.In Li's experiment, this circulation pump accelerated to a rate where the ozone flowing upward and outward from the tropics created a surplus at middle latitudes. Though the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until 2060, the ozone layer over middle latitudes recovered to pre-1980 levels by 2025.The Arctic – which is better connected to mid-latitude air masses than the Antarctic -- benefited from the surplus in the northern hemisphere and from the overall decline of ozone-depleting substances to recover by 2025. Globally averaged ozone and Antarctic concentrations catch up by 2040, as natural atmospheric production of ozone resumes.This recovery in the middle and polar latitudes has mixed consequences, Li noted. It might have some benefits, such as lower levels of ultraviolet radiation reaching the Earth's surface and correspondingly lower rates of skin cancer. On the other hand, it could have unintended effects, such as increasing ozone levels in the troposphere, the layer of atmosphere at Earth's surface. The model also shows a continuing ozone deficit in the stratosphere over the tropics. In fact, when the model run ended at year 2100, the ozone layer over the tropics still showed no signs of recovery.In February, researchers from Johns Hopkins University, Baltimore, teamed with Stolarski and other NASA scientists on a similar paper suggesting that increasing greenhouse gases would delay or even postpone the recovery of ozone levels in the lower stratosphere over some parts of the globe. Using the same model as Li, Stolarski, and Newman, the researchers found that the lower stratosphere over tropical and mid-southern latitudes might not return to pre-1980s levels of ozone for more than a century, if ever.

Ozone Holes

April 12, 2009

https://www.sciencedaily.com/releases/2009/04/090401204201.htm

Carbon Dioxide In Atmosphere Can Now Be Measured From Space

INESC Porto developed a technology, together with ESA – European Space Agency, that enables a more effective measurement of gases in the atmosphere comparatively to the currently used techniques. With this technology, it will be possible to measure gases, such as carbon dioxide, methane, nitrous oxide and ozone – the gases responsible for global warming and greenhouse effects.

The system developed by INESC Porto’s Optoelectronics and Electronic System Unit (UOSE) has a high potential of applicability in satellites due to its efficiency, compactness and reduced volume and mass. The satellites equipped with INESC Porto’s optical fibre filters will be able to detect pollutant gases in the Earth’s atmosphere in concentrations less than 1 km high, at an altitude of 400 km.The partnership between INESC Porto and ESA started in 2006 and is now showing its first signs of success with the development of an optical fibre filter that is capable of measuring carbon dioxide levels from space.Other than carbon dioxide, this technology is capable of providing a precise measurement of other pollutant gases, such as methane gas, nitrous oxide and ozone, besides measuring levels of humidity, atmospheric pressure, temperature and wind speed. Thus, this is an essential tool made in Portugal for research on climate change, a step forward to the control of greenhouse gases in the battle against global warming.If it is applied to satellites, the filter developed by INESC Porto is capable of monitoring all kinds of pollutant gas concentrations less than 1 km high, 50 km wide, at an altitude of 400 km. Unlike what the currently used technologies - atmospheric balloons and airplanes equipped for that purpose -provide, with the filters created by INESC Porto, it will be possible to map the atmosphere three-dimensionally, with a higher resolution and from a single position.The technology's potential of application in orbital systems and scientific missions has to do with its unique features: efficiency, compactness and reduced volume and mass. The technology developed by INESC Porto consists of an ultra-narrow spectral tuneable and heat-reflecting filter based on optical fibre technology that can be used in order to monitor the atmosphere with the reflection of laser impulses. Using the radiation's time of flight and absorption, it will be possible to extract profiles of pollutant gas concentrations in the atmosphere.

Ozone Holes

April 1, 2009

https://www.sciencedaily.com/releases/2009/03/090331153014.htm

Rocket Launches May Need Regulation To Prevent Ozone Depletion, Says Study

The global market for rocket launches may require more stringent regulation in order to prevent significant damage to Earth's stratospheric ozone layer in the decades to come, according to a new study by researchers in California and Colorado.

Future ozone losses from unregulated rocket launches will eventually exceed ozone losses due to chlorofluorocarbons, or CFCs, which stimulated the 1987 Montreal Protocol banning ozone-depleting chemicals, said Martin Ross, chief study author from The Aerospace Corporation in Los Angeles. The study, which includes the University of Colorado at Boulder and Embry-Riddle Aeronautical University, provides a market analysis for estimating future ozone layer depletion based on the expected growth of the space industry and known impacts of rocket launches."As the rocket launch market grows, so will ozone-destroying rocket emissions," said Professor Darin Toohey of CU-Boulder's atmospheric and oceanic sciences department. "If left unregulated, rocket launches by the year 2050 could result in more ozone destruction than was ever realized by CFCs."A paper on the subject by Ross and Manfred Peinemann of The Aerospace Corporation, CU-Boulder's Toohey and Embry-Riddle Aeronautical University's Patrick Ross appeared online in March in the journal Since some proposed space efforts would require frequent launches of large rockets over extended periods, the new study was designed to bring attention to the issue in hopes of sparking additional research, said Ross. "In the policy world uncertainty often leads to unnecessary regulation," he said. "We are suggesting this could be avoided with a more robust understanding of how rockets affect the ozone layer."Current global rocket launches deplete the ozone layer by no more than a few hundredths of 1 percent annually, said Toohey. But as the space industry grows and other ozone-depleting chemicals decline in the Earth's stratosphere, the issue of ozone depletion from rocket launches is expected to move to the forefront.Today, just a handful of NASA space shuttle launches release more ozone-depleting substances in the stratosphere than the entire annual use of CFC-based medical inhalers used to treat asthma and other diseases in the United States and which are now banned, said Toohey. "The Montreal Protocol has left out the space industry, which could have been included."Highly reactive trace-gas molecules known as radicals dominate stratospheric ozone destruction, and a single radical in the stratosphere can destroy up to 10,000 ozone molecules before being deactivated and removed from the stratosphere. Microscopic particles, including soot and aluminum oxide particles emitted by rocket engines, provide chemically active surface areas that increase the rate such radicals "leak" from their reservoirs and contribute to ozone destruction, said Toohey.In addition, every type of rocket engine causes some ozone loss, and rocket combustion products are the only human sources of ozone-destroying compounds injected directly into the middle and upper stratosphere where the ozone layer resides, he said.Although U.S. science agencies spent millions of dollars to assess the ozone loss potential from a hypothetical fleet of 500 supersonic aircraft -- a fleet that never materialized -- much less research has been done to understand the potential range of effects the existing global fleet of rockets might have on the ozone layer, said Ross.Since 1987 CFCs have been banned from use in aerosol cans, freezer refrigerants and air conditioners. Many scientists expect the stratospheric ozone layer -- which absorbs more than 90 percent of harmful ultraviolet radiation that can harm humans and ecosystems -- to return to levels that existed prior to the use of ozone-depleting chemicals by the year 2040.Rockets around the world use a variety of propellants, including solids, liquids and hybrids. Ross said while little is currently known about how they compare to each other with respect to the ozone loss they cause, new studies are needed to provide the parameters required to guide possible regulation of both commercial and government rocket launches in the future."Twenty years may seem like a long way off, but space system development often takes a decade or longer and involves large capital investments," said Ross. "We want to reduce the risk that unpredictable and more strict ozone regulations would be a hindrance to space access by measuring and modeling exactly how different rocket types affect the ozone layer."The research team is optimistic that a solution to the problem exists. "We have the resources, we have the expertise, and we now have the regulatory history to address this issue in a very powerful way," said Toohey. "I am optimistic that we are going to solve this problem, but we are not going to solve it by doing nothing."The research was funded by the National Science Foundation, NASA and The Aerospace Corporation.

Ozone Holes

March 25, 2009

https://www.sciencedaily.com/releases/2009/03/090325155252.htm

Ocean Proximity Aggravates Houston's Ozone Pollution

In Houston, Texas, understanding atmospheric processes that control pollution formation is complicated by both typical urban emissions and large industrial emissions sources—many of the nation's petrochemical facilities are located in southeastern Texas, and these sources release ground-level ozone precursors including nitrogen oxides and highly reactive organic compounds.

Reporting in the During the summer of 2006, nytril chloride mixing ratios of more than 1 part per billion (ppb) were measured in the Houston urban area.Through photochemical modeling, the authors find that nytril chloride increases the total reactive chlorine mass by 20 to 40 percent in the atmosphere of southeastern Texas. The nytril chloride caused widespread increases in ozone concentrations over Houston of 1 to 2 ppb; vertical dispersion and local atmospheric composition moderated the effect of nytril chloride on ozone mixing ratios.The authors include: H. Simon: Center for Energy and Environmental Resources, University of Texas at Austin, Austin, Texas, U.S.A.; now at Atmospheric Modeling and Analysis Division, National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, North Carolina, U.S.A.; Y. Kimura, G. McGaughey, and D. T. Allen: Center for Energy and Environmental Resources, University of Texas at Austin, Austin, Texas, U.S.A.; S. S. Brown, J. M. Roberts: Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado U.S.A.; H. D. Osthoff: Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado U.S.A.; now at Department of Chemistry, University of Calgary, Calgary, Alberta, Canada; D. Byun: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas, U.S.A.; now at Air Resources Laboratory, Office of Ocean and Atmospheric Research, NOAA, Silver Spring, Maryland, U.S.A.; D. Lee: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas, U.S.A.

Ozone Holes

March 19, 2009

https://www.sciencedaily.com/releases/2009/03/090319090754.htm

Ozone: New Simulation Shows Consequences Of A World Without Earth's Natural Sunscreen

The year is 2065. Nearly two-thirds of Earth's ozone is gone -- not just over the poles, but everywhere. The infamous ozone hole over Antarctica, first discovered in the 1980s, is a year-round fixture, with a twin over the North Pole. The ultraviolet (UV) radiation falling on mid-latitude cities like Washington, D.C., is strong enough to cause sunburn in just five minutes. DNA-mutating UV radiation is up 650 percent, with likely harmful effects on plants, animals and human skin cancer rates.

Such is the world we would have inherited if 193 nations had not agreed to ban ozone-depleting substances, according to atmospheric chemists at NASA's Goddard Space Flight Center, Greenbelt, Md., Johns Hopkins University, Baltimore, and the Netherlands Environmental Assessment Agency, Bilthoven.Led by Goddard scientist Paul Newman, the team simulated "what might have been" if chlorofluorocarbons (CFCs) and similar chemicals were not banned through the treaty known as the Montreal Protocol. The simulation used a comprehensive model that included atmospheric chemical effects, wind changes, and radiation changes. The analysis has been published online in the journal Atmospheric Chemistry and Physics."Ozone science and monitoring has improved over the past two decades, and we have moved to a phase where we need to be accountable," said Newman, who is co-chair of the United Nations Environment Programme's Scientific Assessment Panel to review the state of the ozone layer and the environmental impact of ozone regulation. "We are at the point where we have to ask: Were we right about ozone? Did the Montreal Protocol work? What kind of world was avoided by phasing out ozone-depleting substances?"Ozone is Earth's natural sunscreen, absorbing and blocking most of the incoming UV radiation from the sun and protecting life from DNA-damaging radiation. The gas is naturally created and replenished by a photochemical reaction in the upper atmosphere where UV rays break oxygen molecules (O2) into individual atoms that then recombine into three-part molecules (O3). As it is moved around the globe by upper level winds, ozone is slowly depleted by naturally occurring atmospheric gases. It is a system in natural balance.But chlorofluorocarbons -- invented in 1928 as refrigerants and as inert carriers for chemical sprays -- upset that balance. Researchers discovered in the 1970s and 1980s that while CFCs are inert at Earth's surface, they are quite reactive in the stratosphere (10 to 50 kilometers altitude, or 6 to 31 miles), where roughly 90 percent of the planet's ozone accumulates. UV radiation causes CFCs and similar bromine compounds in the stratosphere to break up into elemental chlorine and bromine that readily destroy ozone molecules. Worst of all, such ozone depleting substances can reside for several decades in the stratosphere before breaking down.In the 1980s, ozone-depleting substances opened a wintertime "hole" over Antarctica and opened the eyes of the world to the effects of human activity on the atmosphere. By 1987, the World Meteorological Organization and United Nations Environment Program had brought together scientists, diplomats, environmental advocates, governments, industry representatives, and non-governmental organizations to forge an agreement to phase out the chemicals. In January 1989, the Montreal Protocol went into force, the first-ever international agreement on regulation of chemical pollutants.“The regulation of ozone depleting substances was based upon the evidence gathered by the science community and the consent of industry and government leaders," Newman noted. "The regulation pre-supposed that a lack of action would lead to severe ozone depletion, with consequent severe increases of solar UV radiation levels at the Earth’s surface."In the new analysis, Newman and colleagues "set out to predict ozone losses as if nothing had been done to stop them." Their "world avoided" simulation took months of computer time to process.The team started with the Goddard Earth Observing System Chemistry-Climate Model (GEOS-CCM), an earth system model of atmospheric circulation that accounts for variations in solar energy, atmospheric chemical reactions, temperature variations and winds, and other elements of global climate change. For instance, the new model accounts for how changes in the stratosphere influence changes in the troposphere (the air masses near Earth's surface). Ozone losses change the temperature in different parts of the atmosphere, and those changes promote or suppress chemical reactions.The researchers then increased the emission of CFCs and similar compounds by 3 percent per year, a rate about half the growth rate for the early 1970s. Then they let the simulated world evolve from 1975 to 2065.By the simulated year 2020, 17 percent of all ozone is depleted globally, as assessed by a drop in Dobson Units (DU), the unit of measurement used to quantify a given concentration of ozone. An ozone hole starts to form each year over the Arctic, which was once a place of prodigious ozone levels.By 2040, global ozone concentrations fall below 220 DU, the same levels that currently comprise the "hole" over Antarctica. (In 1974, globally averaged ozone was 315 DU.) The UV index in mid-latitude cities reaches 15 around noon on a clear summer day (a UV index of 10 is considered extreme today.), giving a perceptible sunburn in about 10 minutes. Over Antarctica, the ozone hole becomes a year-round fixture.In the 2050s, something strange happens in the modeled world: Ozone levels in the stratosphere over the tropics collapse to near zero in a process similar to the one that creates the Antarctic ozone hole.By the end of the model run in 2065, global ozone drops to 110 DU, a 67 percent drop from the 1970s. Year-round polar values hover between 50 and 100 DU (down from 300-500 in 1960). The intensity of UV radiation at Earth's surface doubles; at certain shorter wavelengths, intensity rises by as much as 10,000 times. Skin cancer-causing radiation soars."Our world avoided calculation goes a little beyond what I thought would happen," said Goddard scientist and study co-author Richard Stolarski, who was among the pioneers of atmospheric ozone chemistry in the 1970s. "The quantities may not be absolutely correct, but the basic results clearly indicate what could have happened to the atmosphere. And models sometimes show you something you weren't expecting, like the precipitous drop in the tropics.""We simulated a world avoided," said Newman, "and it's a world we should be glad we avoided."The real world of CFC regulation has been somewhat kinder. Production of ozone-depleting substances was mostly halted about 15 years ago, though their abundance is only beginning to decline because the chemicals can reside in the atmosphere for 50 to 100 years. The peak abundance of CFCs in the atmosphere occurred around 2000, and has decreased by roughly 4 percent to date.Stratospheric ozone has been depleted by 5 to 6 percent at middle latitudes, but has somewhat rebounded in recent years. The largest recorded Antarctic ozone hole was recorded in 2006."I didn't think that the Montreal Protocol would work as well as it has, but I was pretty naive about the politics," Stolarski added. "The Montreal Protocol is a remarkable international agreement that should be studied by those involved with global warming and the attempts to reach international agreement on that topic."

Ozone Holes

March 15, 2009

https://www.sciencedaily.com/releases/2009/03/090310152335.htm

Termite Killer Lingers As Potent Greenhouse Gas

Sulfuryl fluoride (SO

The team found that the concentration of the gas rose at a rate of 4 to 6 percent per year between 1978 and 2007, to a global atmospheric abundance by the end of 2007 of about 1.5 parts per trillion. Its actual emissions into the atmosphere over this period were about one third less than estimated from industrial production data."It's extremely important to have independent verification of emissions," said Mühle. "You can't have regulation without verification, and you can't have verification without measurements."The team will report the results of the first-ever measurements of SOMühle said he started detecting an unknown compound in air samples taken in early 2004 at the Scripps pier with a newly developed measurement instrument. He identified the compound as SOWith the help of atmospheric computer models, the Scripps team and colleagues at the Massachusetts Institute of Technology (MIT) determined that the most important removal process of sulfuryl fluoride is dissolution into the ocean, where it is decomposed by chemical reactions. NOAA researchers working with the Scripps team calculated that one kilogram of SOWidespread use of sulfuryl fluoride began in the 1990s following the Montreal Protocol, an international treaty ratified in 1987 to protect the ozone layer by reducing the production of ozone-depleting chemicals. The protocol ordered the gradual discontinuation of methyl bromide, which has strong ozone-depleting characteristics, and sulfuryl fluoride became a preferred replacement for structural fumigation. Sulfuryl fluoride is regulated as a toxic substance but not currently as a greenhouse gas."Such fumigants are very important for controlling pests in the agricultural and building sectors," said Ron Prinn, director of MIT's Center for Global Change Science and a co-author on the new paper. But with methyl bromide being phased out, "industry had to find alternatives, so sulfuryl fluoride has evolved to fill the role.""Unfortunately, it turns out that sulfuryl fluoride is a greenhouse gas with a longer lifetime than previously assumed," added Mühle. "This has to be taken into account before large amounts are emitted into the atmosphere."Mühle credited the assistance of the chief manufacturer of sulfuryl fluoride in the United States, Dow AgroSciences, in the study."They've been very cooperative in sharing with us their estimates of global industrial sulfuryl fluoride production," he said.The team's report follows closely on the announcement of a similar finding about the greater-than-expected prevalence of nitrogen trifluoride, a gas used as a cleaning agent during the manufacture of thin-film solar cells, flat panel monitors and other electronics. The first measurements of nitrogen trifluoride, reported in October, has led to calls for it to be included in the list of greenhouse gases whose emissions are regulated by international treaties. Similar discussions are underway for sulfuryl fluoride. Scripps geochemistry professor Ray Weiss and Scripps researchers Peter Salameh and Christina Harth contributed to the nitrogen trifluoride finding as well as the sulfuryl fluoride research.Researchers from the Massachusetts Institute of Technology, the University of Bristol in the United Kingdom, and the Centre for Australian Weather and Climate Research are co-authors of the sulfuryl fluoride paper.

Ozone Holes

March 12, 2009

https://www.sciencedaily.com/releases/2009/03/090311170627.htm

Long-term Ozone Exposure Linked To Higher Risk Of Death, Finds Nationwide Study

Long-term exposure to ground-level ozone, a major component of smog, is associated with an increased risk of death from respiratory ailments, according to a new nationwide study led by a researcher at the University of California, Berkeley.

The study, to be published in the March 12 issue of the The researchers found that people living in areas with the highest concentrations of ozone, such as the Los Angeles metropolitan area and California's Central Valley, had a 25 to 30 percent greater annual risk of dying from respiratory diseases compared with people from regions with the lowest levels of the pollutant. Those locations included the Great Plains area and regions near San Francisco and Seattle."This is the first time we've been able to connect chronic exposure to ozone, one of the most widespread pollutants in the world, with the risk of death, arguably the most important outcome in health impact studies used to justify air quality regulations," said study lead author Michael Jerrett, UC Berkeley associate professor of environmental health sciences. "Previous research has connected short-term or acute ozone exposure to impaired lung function, aggravated asthma symptoms, increased emergency room visits and hospitalizations, but the impact of long-term exposure to ozone on mortality had not been pinned down until now."The study found that for every 10 parts-per-billion (ppb) increase in ozone level, there is a 4 percent increase in risk of death from respiratory causes, primarily pneumonia and chronic pulmonary obstructive pulmonary disease."World Health Organization data indicate that about 240,000 people die each year from respiratory causes in the United States," said Jerrett. "Even a 4 percent increase can translate into thousands of excess deaths each year. Globally, some 7.7 million people die from respiratory causes, so worldwide the impact of ozone pollution could be very large."The findings come a year after the U.S. Environmental Protection Agency (EPA) strengthened its National Ambient Air Quality Standards for ground-level ozone from an annual average of 80 ppb to 75 ppb to reflect growing evidence of the harmful health effects of ozone. A group of leading scientists appointed to advise the EPA had actually recommended stricter health standards for ozone levels - from 60 to 70 ppb.A month after the EPA released its new standards, a National Research Council report concluded that premature deaths related to ozone exposure of less than 24 hours are more likely among those with pre-existing diseases. The report called for more research on the link between mortality and ozone exposure over a period of weeks and years.Ozone - gas made up of three oxygen atoms - forms a protective layer from the sun's ultraviolet radiation when located in the Earth's upper atmosphere. However, that same gas is toxic at ground level where it can be breathed by humans. Ground level ozone is formed through a complex chemical reaction in sunlight between nitrogen oxides (NOx), commonly spewed from vehicle exhaust, and industrial factory emissions.The Intergovernmental Panel on Climate Change considers ground-level ozone, along with carbon dioxide and methane, to be one of the primary greenhouse gases in the Earth's atmosphere."Ozone levels outdoors are not always highly correlated to ozone levels indoors, making it difficult to fully evaluate associations between ozone and health outcomes using ambient site monitors," said study co-author C. Arden Pope III, professor of economics at Brigham Young University. "The reality is that most of us spend the majority of our time indoors. But this study suggests that repeated exposures to elevated ozone levels over time have cumulative effects on respiratory health."The new study analyzed data from 448,850 adults ages 30 and older enrolled in 1982 and 1983 in the American Cancer Society Cancer Prevention Study II.The researchers correlated the information from that study with data from EPA air pollution monitors while controlling for potentially confounding factors such as a participant's age, race, education, occupational exposures, smoking history and diet. The study also factored in other variables such as unemployment rates in the metropolitan and zip code area levels.Ozone data were obtained from 1977 through 2000 between the months of April and September. Those months were chosen because ozone levels are typically higher when it's warmer and because insufficient data was available during the cooler months.Researchers included EPA measurements of fine particulate matter – particles equal to or smaller than 2.5 micrometers in diameter and typically found in smoke and haze – when they became available in 1999 and 2000. Because fine particle levels had already been linked to increased risk of premature death in previous studies, the researchers included them in the analysis to distinguish the effects of the two pollutants.In an 18-year follow-up period, 48,884 of the people in the study died from cardiovascular causes such as heart disease and strokes, and 9,891 died from respiratory causes.As has been observed in previous studies, the researchers found that fine particulate matter was linked to an increased risk of death from cardiovascular causes when analyzed alone and with ozone. The new finding was that the effects of ozone remained strongly linked to risk of death from respiratory problems, even after fine particle pollution was taken into account.Not surprisingly, highly populated regions such as the Los Angeles, Riverside and Houston areas, where the climate is sunny for much of the year and the air mass is relatively stable, had the highest average concentrations of ozone, ranging from 62.5 to 104 ppb. The regions with the lowest ozone levels had average concentrations of 33.3 to 53.1 ppb."Places like the Pacific Northwest and the Minneapolis St. Paul region are cooler and see more rain in the summer, which keeps the ozone levels in check," said Jerrett. "Similarly, the San Francisco Bay Area's infamous summertime fog blocks the sun and helps protect the region from high ozone levels."Because ozone formation depends on a complex interaction of multiple factors, it is challenging to regulate, the study authors said. "Our study for the first time presents evidence suggesting that long-term exposure to ozone and fine particle pollution have separate, independent effects on mortality, and that they seem to impact different parts of the body," said Jerrett. "With this research, we now know that controlling ozone is not only beneficial for mitigating global warming, but that it could also have near-term benefits in the reduction of deaths from respiratory causes."Other co-authors of the paper are Richard Burnett from Health Canada, the federal health department headquartered in Ottawa; Kaz Ito and George Thurston from the New York University School of Medicine; Daniel Krewski and Dr. Yuanli Shi from the University of Ottawa; and Eugenia Calle and Dr. Michael Thun from the American Cancer Society.The Health Effects Institute, a non-profit research organization based in Boston, Mass., helped support this research.An EPA list of where U.S. counties stand in compliance with the current federal ozone standards is available at

Ozone Holes

March 10, 2009

https://www.sciencedaily.com/releases/2009/02/090225132343.htm

European Satellites Provide New Insight Into Ozone-depleting Species

Using data from the satellite-based MIPAS and GOME-2 instruments, scientists have for the first time detected important bromine species in the atmosphere. These new measurements will help scientists to better understand sources of ozone-depleting species and to improve simulations of stratospheric ozone chemistry.

Despite the detection of bromine monoxide (BrO) in the atmosphere some 20 years ago, bromine nitrate (BrONO2) was first observed in 2008 when scientists from the Karlsruhe Institute of Technology discovered the gas’s weak signal with data from MIPAS (the Michelson Interferometer for Passive Atmospheric Sounding)."By comparing the novel MIPAS BrONO2 dataset with model calculations and BrO measurements by SCIAMACHY on Envisat, our general understanding of stratospheric bromine chemistry has been clearly confirmed," said Michael Höpfner of Germany’s Karlsruhe Institute of Technology. "These new observations also enable an independent estimation of the total amount of bromine in the stratosphere, which is important for understanding the origins of stratospheric bromine."  The stratospheric ozone layer that protects life on Earth from harmful ultraviolet rays is vulnerable to the presence of certain chemicals in the atmosphere such as chlorine and bromine. In spite of its much smaller concentrations, bromine is actually, after chlorine, the second most important halogen species destroying ozone in the stratosphere.Since chlorine levels in the stratosphere have been dropping since the ban on man-made chlorofluorocarbons (CFCs), bromine will become even more important in stratospheric ozone chemistry. Bromine’s importance will increase in part because there are more natural sources, such as volcanoes, for bromine emissions than for chlorine.Volcanoes have long been known to play an important role in influencing stratospheric ozone chemistry because of the gases and particles they shoot into the atmosphere. New findings from space suggest they are also a very important source of atmospheric bromine.The reactive chemical bromine monoxide (BrO) has been measured in a number of volcanic plumes around the globe, but until recently it had never been measured by a space instrument.In August 2008, the Kasatochi Volcano in Alaska's Aleutian Islands erupted explosively, sending a cloud of volcanic ash and gas more than 11 km into the atmosphere.The following day, scientists from the Brussels-based Belgian Institute for Space Aeronomy identified high bromine concentrations in the vicinity of the volcano with Envisat’s SCIAMACHY instrument and the Global Ozone Monitoring Experiment-2 (GOME-2) instrument aboard MetOp-A. (MetOp-A, developed by ESA and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), is Europe's first polar-orbiting satellite dedicated to operational meteorology.)"Because of the good regional coverage of the GOME-2 instrument, the transport of the Kasatochi BrO plume could be followed for six days after the eruption," Michel Van Roozendael from the Belgian Institute for Space Aeronomy said. "Using the Lagrangian dispersion model, results show that the volcanic BrO was directly injected into the upper troposphere/lower stratosphere at altitudes ranging from 8 to 12 km."The total mass of reactive bromine released in the atmosphere was estimated around 50 to 120 tons, which corresponds to approximately 25% of the previously estimated total annual mass of reactive bromine emitted by volcanic activity."

Ozone Holes

February 26, 2009

https://www.sciencedaily.com/releases/2009/02/090225073215.htm

Ice Declining Faster Than Expected In Both Arctic And Antarctic Glaciers

Multidisciplinary research from the International Polar Year (IPY) 2007-2008 provides new evidence of the widespread effects of global warming in the polar regions. Snow and ice are declining in both polar regions, affecting human livelihoods as well as local plant and animal life in the Arctic, as well as global ocean and atmospheric circulation and sea level.

These are but a few findings reported in “State of Polar Research”, released February 25 by the World Meteorological Organization (WMO) and the International Council for Science (ICSU). In addition to lending insight into climate change, IPY has aided our understanding of pollutant transport, species’ evolution, and storm formation, among many other areas.The wide-ranging IPY findings result from more than 160 endorsed science projects assembled from researchers in more than 60 countries. Launched in March 2007, the IPY covers a two-year period to March 2009 to allow for observations during the alternate seasons in both polar regions. A joint project of WMO and ICSU, IPY spearheaded efforts to better monitor and understand the Arctic and Antarctic regions, with international funding support of about US$ 1.2 billion over the two-year period.IPY has provided a critical boost to polar research during a time in which the global environment is changing faster than ever in human history. It now appears clear that the Greenland and Antarctic ice sheets are losing mass contributing to sea level rise.  Warming in the Antarctic is much more widespread than it was thought prior to the IPY, and it now appears that the rate of ice loss from Greenland is increasing.Researchers also found that in the Arctic, during the summers of 2007 and 2008, the minimum extent of year-round sea ice decreased to its lowest level since satellite records began 30 years ago. IPY expeditions recorded an unprecedented rate of sea-ice drift in the Arctic as well. Due to global warming, the types and extent of vegetation in the Arctic shifted, affecting grazing animals and hunting.Other evidence for global warming comes from IPY research vessels that have confirmed above-global-average warming in the Southern Ocean. A freshening of the bottom water near Antarctica is consistent with increased ice melt from Antarctica and could affect ocean circulation. Global warming is thus affecting Antarctica in ways not previously identified.IPY research has also identified large pools of carbon stored as methane in permafrost. Thawing permafrost threatens to destabilize the stored methane -a greenhouse gas- and send it into the atmosphere. Indeed, IPY researchers along the Siberian coast observed substantial emissions of methane from ocean sediments.In the area of biodiversity, surveys of the Southern Ocean have uncovered a remarkably rich, colourful and complex range of life. Some species appear to be migrating poleward in response to global warming. Other IPY studies reveal interesting evolutionary trends such as many present-day deep-sea octopuses having originated from common ancestor species that still survive in the Southern Ocean.IPY has also given atmospheric research new insight. Researchers have discovered that North Atlantic storms are major sources of heat and moisture for the polar regions. Understanding these mechanisms will improve forecasts of the path and intensity of storms. Studies of the ozone hole have benefited from IPY research as well, with new connections identified between the ozone concentrations above Antarctica and wind and storm conditions over the Southern Ocean. This information will improve predictions of climate and ozone depletion.Many Arctic residents, including indigenous communities, participated in IPY’s projects. Over 30 of these projects addressed Arctic social and human science issues, including food security, pollution, and other health issues, and will bring new understanding to addressing these pressing challenges. “IPY has been the catalyst for the development and strengthening of community monitoring networks across the North” said David Carlson, Director of the IPY International Programme Office. “These networks stimulate the information flow among communities and back and forth from science to communities.”The increased threats posed by climate change make polar research a special priority. The “State of Polar Research” document not only describes some of the striking discoveries during IPY, it also recommends priorities for future action to ensure that society is best informed about ongoing polar change and its likely future evolution and global impacts. A major IPY science conference will take place in Oslo in June 2010.

Ozone Holes

February 5, 2009

https://www.sciencedaily.com/releases/2009/02/090204131625.htm

Global Warming May Delay Recovery Of Stratospheric Ozone

Increasing greenhouse gases could delay, or even postpone indefinitely the recovery of stratospheric ozone in some regions of the Earth, a new study suggests. This change might take a toll on public health.

Darryn W. Waugh, an atmospheric scientist at Johns Hopkins University in Baltimore, and his colleagues report that climate change could provoke variations in the circulation of air in the lower stratosphere in tropical and southern mid-latitudes — a band of the Earth including Australia and Brazil. The circulation changes would cause ozone levels in these areas never to return to levels that were present before decline began, even after ozone-depleting substances have been wiped out from the atmosphere."Global warming causes changes in the speed that the air is transported into and through the lower stratosphere [in tropical and southern mid-latitudes]," says Waugh. "You're moving the air through it quicker, so less ozone gets formed." He and his team present their findings in the journal Dan Lubin, an atmospheric scientist who has studied the relationship between ozone depletion and variations in the ultraviolet radiation that reaches the Earth, says Waugh's findings could bode ill for people living in the tropics and southern mid-latitudes.If ozone levels never return to pre-1960 levels in those regions, "the risk of skin cancer for fair-skinned populations living in countries like Australia and New Zealand, and probably in Chile and Argentina too, will be greater in the 21st century than it was during the 20th century," says Lubin, who is at Scripps Institution of Oceanography in La Jolla, Calif. and did not participate in the research.Ozone is a gas which is naturally present in the atmosphere and absorbs ultraviolet radiation from the Sun that can harm living beings—for instance, by causing human skin cancer. This protective molecule has been in decline in the stratosphere since the 1970s due to an increase in atmospheric concentrations of human-made substances (mostly chlorofluorocarbon and bromofluorocarbon compounds) that destroy ozone. Since the late 1980s, most countries have adhered to the Montreal Protocol, an international treaty to phase out production of ozone-depleting substances.Researchers at NASA Goddard Space Flight Center in Greenbelt, Md. collaborated with Waugh in the new study. The team forecast effects on ozone recovery by means of simulations using a computer model known as the Goddard Earth Observing System Chemistry-Climate Model.Not all regions face worse prospects for ozone recovery as a result of climate change, the scientists find.In polar regions and northern mid-latitudes, restoration of ozone in the lower stratosphere will suffer little impact from increasing greenhouse gases, their projections indicate.Indeed, in the upper stratosphere, climate change causes a drop in temperatures that slows down some of the chemical reactions that destroy ozone. So, recovery might be reached in those parts of the atmosphere earlier than forecast, even decades before the removal of ozone-depleting gases.While scientists have long suspected that climate change might be altering the dynamics of stratospheric ozone recovery, Waugh's team is the first to estimate the effects of increasing greenhouse gases on the recovery of ozone by region.Waugh says his study will help scientists attribute ozone variations to the right agent."Ozone is going to change in response to both ozone-depleting substances and greenhouse gases," he says, "If you don't consider climate change when studying the ozone recovery data, you may get pretty confused."

Ozone Holes

January 30, 2009

https://www.sciencedaily.com/releases/2009/01/090121144059.htm

Termite Insecticide Found To Be Potent Greenhouse Gas

An insecticide used to fumigate termite-infested buildings is a strong greenhouse gas that lives in the atmosphere nearly 10 times longer than previously thought, UC Irvine research has found.

Sulfuryl fluoride, UCI chemists discovered, stays in the atmosphere at least 30-40 years and perhaps as long as 100 years. Prior studies estimated its atmospheric lifetime at as low as five years, grossly underestimating the global warming potential.The fact that sulfuryl fluoride exists for decades – coupled with evidence that levels have nearly doubled in the last six years – concerns study authors Mads Sulbaek Andersen, Donald Blake and Nobel Laureate F. Sherwood Rowland, who discovered that chlorofluorocarbons in aerosol cans and other products damage the ozone layer. That finding led to a worldwide ban on CFCs.“Sulfuryl fluoride has a long enough lifetime in the atmosphere that we cannot just close our eyes,” said Sulbaek Andersen, a postdoctoral researcher in the Rowland-Blake laboratory and lead author of the study. “The level in the atmosphere is rising fast, and it doesn’t seem to disappear very quickly.”This study appears online Jan. 21 in the journal Environmental Science and Technology.Kilogram for kilogram, sulfuryl fluoride is about 4,000 times more efficient than carbon dioxide at trapping heat, though much less of it exists in the atmosphere.Its climate impact in California each year equals that of carbon dioxide emitted from about 1 million vehicles. About 60 percent of the world’s sulfuryl fluoride use occurs in California.Sulfuryl fluoride blocks a wavelength of heat that otherwise could easily escape the Earth, the scientists said. Carbon dioxide blocks a different wavelength, trapping heat near the surface.“The only place where the planet is able to emit heat that escapes the atmosphere is in the region that sulfuryl fluoride blocks,” said Blake, chemistry professor. “If we put something with this blocking effect in that area, then we’re in trouble – and we are putting something in there.”The chemists worry that emissions will increase as new uses are found for sulfuryl fluoride – especially given the ban of methyl bromide, an ozone-depleting pesticide regulated under the Montreal Protocol. Sulfuryl fluoride emissions are not regulated, though officials do consider it a toxic contaminant.The insecticide is pumped into a tent that covers a termite-infested structure. When the tent is removed, the compound escapes into the atmosphere. Sulbaek Andersen, Blake and Rowland believe a suitable replacement should be found, one with less global warming potential.To measure sulfuryl fluoride’s atmospheric lifetime, the chemists put it inside a Pyrex chamber with compounds that are well understood in the atmosphere, such as ethane. They shined lamps on the chamber to simulate sunlight, which caused chemical reactions that eliminated the compounds from the air.By monitoring sulfuryl fluoride changes compared with changes to the well-known compounds, they were able to estimate its atmospheric lifetime.“This is a cautionary paper,” said Rowland, Donald Bren Research Professor of Chemistry and Earth System Science. “It tells us that we need to be thinking globally – and acting locally.”M.D. Hurley and T.J. Wallington of Ford Motor Co.’s Systems Analytics & Environmental Sciences Department also worked on this study, which was funded in part by the Comer Foundation.

Ozone Holes

January 22, 2009

https://www.sciencedaily.com/releases/2009/01/090121144049.htm

Much Of Antarctica Is Warming More Than Previously Thought

Scientists studying climate change have long believed that while most of the rest of the globe has been getting steadily warmer, a large part of Antarctica – the East Antarctic Ice Sheet – has actually been getting colder.

But new research shows that for the last 50 years, much of Antarctica has been warming at a rate comparable to the rest of the world. In fact, the warming in West Antarctica is greater than the cooling in East Antarctica, meaning that on average the continent has gotten warmer, said Eric Steig, a University of Washington professor of Earth and space sciences and director of the Quaternary Research Center at the UW."West Antarctica is a very different place than East Antarctica, and there is a physical barrier, the Transantarctic Mountains, that separates the two," said Steig, lead author of a paper documenting the warming published in the Jan. 22 edition of Nature.For years it was believed that a relatively small area known as the Antarctic Peninsula was getting warmer, but that the rest of the continent – including West Antarctica, the ice sheet most susceptible to potential future collapse – was cooling.Steig noted that the West Antarctic Ice Sheet, with an average elevation of about 6,000 feet above sea level, is substantially lower than East Antarctica, which has an average elevation of more than 10,000 feet. While the entire continent is essentially a desert, West Antarctica is subject to relatively warm, moist storms and receives much greater snowfall than East Antarctica.The study found that warming in West Antarctica exceeded one-tenth of a degree Celsius per decade for the last 50 years and more than offset the cooling in East Antarctica.Co-authors of the paper are David Schneider of the National Center for Atmospheric Research in Boulder, Colo., a former student of Steig's; Scott Rutherford of Roger Williams University in Bristol, R.I.; Michael Mann of Pennsylvania State University; Josefino Comiso of NASA's Goddard Space Flight Center in Greenbelt, Md.; and Drew Shindell of NASA's Goddard Institute for Space Studies in New York City. The work was supported by grants from the National Science Foundation.The researchers devised a statistical technique that uses data from satellites and from Antarctic weather stations to make a new estimate of temperature trends."People were calculating with their heads instead of actually doing the math," Steig said. "What we did is interpolate carefully instead of just using the back of an envelope. While other interpolations had been done previously, no one had really taken advantage of the satellite data, which provide crucial information about spatial patterns of temperature change."Satellites calculate the surface temperature by measuring the intensity of infrared light radiated by the snowpack, and they have the advantage of covering the entire continent. However, they have only been in operation for 25 years. On the other hand, a number of Antarctic weather stations have been in place since 1957, the International Geophysical Year, but virtually all of them are within a short distance of the coast and so provide no direct information about conditions in the continent's interior.The scientists found temperature measurements from weather stations corresponded closely with satellite data for overlapping time periods. That allowed them to use the satellite data as a guide to deduce temperatures in areas of the continent without weather stations."Simple explanations don't capture the complexity of climate," Steig said. "The thing you hear all the time is that Antarctica is cooling and that's not the case. If anything it's the reverse, but it's more complex than that. Antarctica isn't warming at the same rate everywhere, and while some areas have been cooling for a long time the evidence shows the continent as a whole is getting warmer."A major reason most of Antarctica was thought to be cooling is because of a hole in the Earth's protective ozone layer that appears during the spring months in the Southern Hemisphere's polar region. Steig noted that it is well established that the ozone hole has contributed to cooling in East Antarctica."However, it seems to have been assumed that the ozone hole was affecting the entire continent when there wasn't any evidence to support that idea, or even any theory to support it," he said."In any case, efforts to repair the ozone layer eventually will begin taking effect and the hole could be eliminated by the middle of this century. If that happens, all of Antarctica could begin warming on a par with the rest of the world."

Ozone Holes

December 24, 2008

https://www.sciencedaily.com/releases/2008/12/081215111305.htm

Does Global Warming Lead To A Change In Upper Atmospheric Transport?

Most atmospheric models predict that the rate of transport of air from the troposphere to the above lying stratosphere should be increasing due to climate change. Surprisingly, Dr. Andreas Engel together with an international group of researchers has now found that this does not seem to be happening. On the contrary, it seems that the air air masses are moving more slowly than predicted. This could also imply that recovery of the ozone layer may be somewhat slower than predicted by state-of-the-art atmospheric climate models.

The researchers investigated the time it takes to transport the atmospheric trace gases sulfurhexafluoride (SF6) and carbon dioxide (COAs these measurements are quite complex and expensive, they can only be performed sporadically. In cooperation with German, American and Japanese colleagues, the group gathered all measurements of these trace gases available world-wide. For this purpose, archived air samples which were collected more than 30 years ago in the stratosphere above North American, have been analysed in Frankfurt. Andreas Engel explains that "Sulfurhexafluoride is amongst the most stable gases in the atmosphere, meaning that using today's analytical techniques, it is possible to analyse even extremely small amounts present in the 30 year-old air samples."While state-of-the-art climate models predict an increase in stratospheric transport and thus younger ages, the measurements indicate that the age seems to have increased slightly, meaning that the transport rates have not increased. The Frankfurt research group wants to continue the long-term measurement series in order to provide further measurements which can help to evaluate the model predictions and document the long-term evolution of the atmosphere. Due to the results presented now, the predictions of atmospheric models must be re-evaluated. Andreas Engel emphasises that "our results do not contradict the principal global change predicted by the models, yet the exact mechanisms of how this influences transport of air in the upper atmosphere do not seem to be fully understood. More research is needed here."

Ozone Holes

December 10, 2008

https://www.sciencedaily.com/releases/2008/12/081209085628.htm

Surface-Level Ozone Pollution Set To Reduce Tree Growth 10% By 2100

Modern day concentrations of ground level ozone pollution are decreasing the growth of trees in the northern and temperate mid-latitudes, as shown in a paper publishing December 9 in Global Change Biology. Tree growth, measured in biomass, is already 7% less than the late 1800s, and this is set to increase to a 17% reduction by the end of the century.

Ozone pollution is four times greater now than prior to the Industrial Revolution in the mid-1700s; if modern dependence on fossil fuels continues at the current pace, future ozone concentrations will be at least double current levels by the end of this century with the capacity to further decrease the growth of trees.The study is the first statistical summary of individual experimental measurements of how ozone will damage the productivity of trees, including data from 263 peer-reviewed scientific publications.Ozone is the third strongest greenhouse gas, directly contributing to global warming, and is the air pollutant considered to be the most damaging to plants. But more importantly, it has the potential to leave more carbon dioxide, ranked as the first strongest greenhouse gas, in the atmosphere by decreasing carbon assimilation in trees. Ozone pollution occurs when nitrogen oxides have a photochemical reaction with volatile organic compounds.“This research quantifies the mean response of trees to ozone pollution measured in terms of total tree biomass, and all component parts such as leaf, root and shoot, lost due to ozone pollution,” said Dr. Victoria Wittig, lead author of the study. “Looking at how ozone pollution affects trees is important because of the indirect impact on carbon dioxide concentrations in the atmosphere which will further enhance global warming, in addition to ozone’s already potent direct impact.”In addition to ozone pollution reducing the strength of trees to hold carbon in the northern temperate mid-latitudes by reducing tree growth, the research also indicates that broad-leaf trees, such as poplars, are more sensitive to ozone pollution than conifers, such as pines, and that root growth is suppressed more than aboveground growth.“Beyond the consequences for global warming, the study also infers that in mixed forests conifers will be favored over broad-leaved trees, and that the decrease in root size will increase the vulnerability to storms,” said Wittig.

Ozone Holes

November 24, 2008

https://www.sciencedaily.com/releases/2008/11/081122083325.htm

Climate Change May Boost Exposures To Harmful Pollutants

A review of studies projecting the impact of climate change on air quality, including effects on morbidity and mortality, indicates that adverse health effects will likely rise with changes in pollutant creation, transport, dispersion, and deposition. However, reducing greenhouse gas emissions could go far in mitigating adverse effects.

Worldwide, 800,000 deaths and 7.9 million disability-adjusted life-years lost from respiratory problems, lung disease, and cancer were attributed to urban air pollution in 2000, according to the World Health Organization.Ground-level ozone is a known pulmonary irritant that affects the respiratory mucous membranes, other lung tissues, and respiratory function. Exposure to elevated concentrations of ozone is associated with increased hospital admissions for pneumonia, chronic obstructive pulmonary disease, asthma, allergic rhinitis, and other respiratory diseases, and with premature mortality.“Projections suggest that climate change will increase concentrations of tropospheric ozone, at least in high-income countries when precursor emissions are held constant, which would increase morbidity and mortality,” wrote authors Kristie L. Ebi and Glenn McGregor. "The potential impacts of climate change on ozone concentrations have not been projected for low-income countries, many of which currently have significantly higher ozone exposures."Additional research is needed to better project the health impacts of changing concentrations of ozone due to climate change. Sources of uncertainty include the projected degree of future climate change, the impact of future emissions and their pathways, potential changing weather patterns, the severity of episodes of poor air quality, and changes in population vulnerability.These findings appear in the November 2008 issue of the peer-reviewed journal, Environmental Health Perspectives (EHP).

Ozone Holes

November 22, 2008

https://www.sciencedaily.com/releases/2008/11/081107072003.htm

Snow In The Arctic: An Ingredient In A Surprising Chemical Cocktail

In the Arctic in spring, the snow cover gives off nitrogen oxides. This phenomenon, the extent of which had not been previously realized, is the source of one third of the nitrates present in the Arctic atmosphere, according to researchers from CNRS, the Université Joseph Fourier and the Université Pierre et Marie Curie[1].

They made a quantitative study of the origin and evolution of nitrogen compounds in the Arctic atmosphere, in order to understand their environmental impact on this region. These findings are published in the 31 October 2008 issue of the journal Science.In the Arctic, the snow that covers the land mass and the pack ice is a constant source of new surprises for researchers. One of the major players in climate change, it is also closely monitored by atmospheric chemists, who suspect it of being behind fundamental alterations in atmospheric composition in spring, when sunshine returns.The researchers had already studied episodes of total destruction of ozone at the surface of the Arctic snow cover [2] as well as the role played by this cover in the dangerous mercury 'rain' that pollutes ecosystems [3]. This time they were interested in the ability of the arctic snow cover to interact with nitrogen compounds such as nitrogen oxides and atmospheric nitrate. At temperate latitudes nitrogen oxides are produced not only by natural phenomena such as lightning and forest fires, but also by human activity, such as combustion in engines and industrial activity. They are the cause of the peaks in ozone concentration observed on the outskirts of cities during episodes of high pollution. Nitrogen oxides are rapidly oxidized to nitrate, which, incorporated into atmospheric particulate matter, is transported by air currents, bringing surplus nitrogen to distant ecosystems.In the Arctic, in autumn, winter and spring, the nitrate is deposited onto the snow cover. Then, when the snow is exposed to solar radiation, the nitrate turns into nitrogen oxides that are emitted to the atmosphere, causing disturbances in Arctic atmospheric chemistry. However, the extent of this phenomenon remained to be quantified.By measuring the isotopic composition of the nitrogen and oxygen in the atmospheric nitrate collected in the Canadian Arctic (Alert station, Nunavut)[4], the researchers have shown that the 'recycling' of nitrate deposited on the snow of the Arctic pack ice returns nitrogen oxides to the atmosphere in substantial quantities. For instance, in spring, nearly one third of the Arctic atmospheric nitrate comes from emissions of nitrogen oxides from the snow cover, while the rest comes directly from atmospheric transport from middle latitudes. The researchers also show that there are strong chemical interactions between the nitrogen oxides emitted by the snow cover and the halogenated compounds (in particular BrO radicals) that are involved in the phenomena of ozone destruction in the lower levels of the atmosphere in spring.This study highlights the close links between the climate system (ice surfaces, snow-covered surfaces, temperatures, and percentage of solar radiation reaching the Earth's surface) and the presence of highly reactive pollutants in the Arctic atmosphere (nitrogen oxides, ozone, and particulate matter emitted by human activity). It shows the need for a global approach to environmental problems, calling for long-term monitoring and the use of new techniques for analyzing processes.The work was funded by CNRS's National Institute of Earth Sciences and Astronomy (INSU), the Institut Polaire - Paul Émile Victor (IPEV) and by a European Science Foundation program (EUROCORE-EuroCLIMATE).[1] Laboratoire de glaciologie et de géologie de l’environnement (CNRS/Université Joseph Fourier), Laboratoire d’étude des transferts en hydrologie et environnement (CNRS/Université Joseph Fourier/Institut polytechnique de Grenoble), Service d'aéronomie (CNRS/Université Pierre et Marie Curie/Université Versailles Saint Quentin)[2] [3] [4] by the Meteorological Service of Canada ( Global Atmospheric Watch program, coordinated by the World Meteorological Organization).

Ozone Holes

November 6, 2008

https://www.sciencedaily.com/releases/2008/11/081105175154.htm

2008 Sees Fifth Largest Ozone Hole

The ozone hole over Antarctica, which fluctuates in response to temperature and sunlight, grew to the size of North America in a one-day maximum in September that was the fifth largest on record, since NOAA satellite records began in 1979.

The Antarctic ozone hole reached its annual maximum on Sept. 12, 2008, stretching over 27 million kilometers, or 10.5 square miles. The area of the ozone hole is calculated as an average of the daily areas for Sept. 21-30 from observations from the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite.NOAA scientists, who have monitored the ozone layer since 1962, have determined that this year’s ozone hole has passed its seasonal peak for 2008. Data is available at online.The primary cause of the ozone hole is human-produced compounds called chlorofluorocarbons, or CFCs, which release ozone-destroying chlorine and bromine into the atmosphere. Earth’s protective ozone layer acts like a giant umbrella, blocking the sun’s ultraviolet-B rays. Though banned for the past 21 years to reduce their harmful build up, CFCs still take many decades to dissipate from the atmosphere.According to NOAA scientists, colder than average temperatures in the stratosphere may have helped play a part in allowing the ozone hole to develop more fully this year.“Weather is the most important factor in the fluctuation of the size of the ozone hole from year-to-year,” said Bryan Johnson, a scientist at NOAA’s Earth System Research Laboratory in Boulder, which monitors ozone, ozone-depleting chemicals, and greenhouse gases around the globe. “How cold the stratosphere is and what the winds do determine how powerfully the chemicals can perform their dirty work.”NASA satellites measured the maximum area of this year’s ozone hole at 10.5 million square miles and four miles deep, on Sept. 12. Balloon-borne sensors released from NOAA’s South Pole site showed the total column of atmospheric ozone dropped to its lowest count of 107 Dobson units on Sept. 28. Dobson units are a measure of total ozone in a vertical column of air.In 2006, record-breaking ozone loss occurred as ozone thickness plunged to 93 Dobson units on Oct. 9 and sprawled over 11.4 million square miles at its peak. Scientists blamed colder-than-usual temperatures in the stratosphere for its unusually large size. Last year’s ozone hole was average in size and depth.Starting in May, as Antarctica moves into a period of 24-hour-a-day darkness, rotating winds the size of the continent create a vortex of cold, stable air centered near the South Pole that isolates CFCs over the continent. When spring sunshine returns in August, the sun’s ultraviolet light sets off a series of chemical reactions inside the vortex that consume the ozone. The colder and more isolated the air inside the vortex, the more destructive the chemistry. By late December the southern summer is in full swing, the vortex has crumbled, and the ozone has returned—until the process begins anew the following winter.The 1987 Montreal Protocol and other regulations banning CFCs reversed the buildup of chlorine and bromine, first noticed in the 1980s.“These chemicals—and signs of their reduction—take several years to rise from the lower atmosphere into the stratosphere and then migrate to the poles,” said NOAA’s Craig Long, a research meteorologist at NOAA’s National Centers for Environmental Prediction. “The chemicals also typically last 40 to 100 years in the atmosphere. For these reasons, stratospheric CFC levels have dropped only a few percent below their peak in the early 2000s.““The decline of these harmful substances to their pre-ozone hole levels in the Antarctic stratosphere will take decades,” said NOAA atmospheric chemist Stephen Montzka of the Earth System Research Laboratory. “We don’t expect a full recovery of Antarctic ozone until the second half of the century.”

Ozone Holes

November 6, 2008

https://www.sciencedaily.com/releases/2008/10/081030144618.htm

Conclusive Proof That Polar Warming Is Being Caused By Humans

New research by the University of East Anglia (UEA) has demonstrated for the first time that human activity is responsible for significant warming in both polar regions.

The findings by a team of scientists led by UEA's Climatic Research Unit was recently published online by the Nature Geoscience.Previous studies have observed rises in both Arctic and Antarctic temperatures over recent decades but have not formally attributed the changes to human influence due to poor observation data and large natural variability. Moreover, the International Panel on Climate Change (IPCC) had concluded that Antarctica was the only continent where human-induced temperature changes had yet to be detected.Now, a newly updated data-set of land surface temperatures and simulations from four new climate models show that temperature rises in both polar regions are not consistent with natural climate variability alone and are directly attributable to human influence.The results demonstrate that human activity has already caused significant warming, with impacts on polar biology, indigenous communities, ice-sheet mass balance and global sea level."This is an important work indeed," said Dr Alexey Karpechko of UEA's Climatic Research Unit."Arctic warming has previously been emphasized in several publications, although not formally attributed to human activity. However in Antarctica, such detection was so far precluded by insufficient data available. Moreover circulation changes caused by stratospheric ozone depletion opposed warming over most of Antarctica and made the detection even more difficult."Since the ozone layer is expected to recover in the future we may expect amplifying Antarctic warming in the coming years."Authors of the article 'Attribution of polar warming to human influence' include Nathan Gillett (UEA/Environment Canada), Phil Jones (UEA), Alexey Karpechko (UEA), Daithi Stone (University of Oxford/Tyndall Centre for Climate Change Research), Peter Scott (Met Office Hadley Centre), Toru Nozawa (National Institute for Environmental Studies, Japan), Gabriele Hegerl (University of Edinburgh), and Michael Wehner (Lawrence Berkeley National Laboratory, California).

Ozone Holes

October 18, 2008

https://www.sciencedaily.com/releases/2008/10/081009144115.htm

Wildfires Cause Ozone Pollution To Violate Health Standards, New Study Shows

Wildfires can boost ozone pollution to levels that violate U.S. health standards, a new study concludes. The research, by scientists at the National Center for Atmospheric Research (NCAR), focused on California wildfires in 2007, finding that they repeatedly caused ground-level ozone to spike to unhealthy levels across a broad area, including much of rural California as well as neighboring Nevada.

The study was published today in Geophysical Research Letters. It was funded by NASA and by the National Science Foundation, which sponsors NCAR."It's important to understand the health impacts of wildfires," says NCAR scientist Gabriele Pfister, the lead author. "Ozone can hit unhealthy levels even in places where people don't see smoke."Although scientists have long known that wildfires can affect air quality by emitting particles and gases into the air, there has been little research to quantify the impacts. Fires worsen ozone levels by releasing nitrogen oxides and hydrocarbons, which can form ozone near the fire or far downwind as a result of chemical reactions in sunlight.The researchers, using a combination of computer models and ground-level measurements, studied intense California wildfires that broke out in September and October of 2007. They found that ozone was three times more likely to violate safe levels when fire plumes blew into a region than when no plumes were present.At the time of the wildfires, the public health standard for ozone set by the Environmental Protection Agency (EPA) was 0.08 parts per million over an eight-hour period. The EPA has since tightened the standard to 0.075 parts per million. Under the stricter standard, the number of violations would have nearly doubled.While ozone in the stratosphere benefits life on Earth by blocking ultraviolet radiation from the Sun, ozone in the lower atmosphere can trigger a number of health problems. These range from coughing and throat irritation to more serious problems, such as aggravation of asthma, bronchitis, and emphysema. Ground-level ozone pollution also damages crops and other plants."Wildfires are expected to worsen in the future, especially as our climate grows warmer," Pfister says. "But we are only now beginning to understand their potential impacts on people and ecosystems, not only nearby but also potentially far downwind."The unhealthy levels of ozone the researchers detected occurred mostly in rural areas. This finding may be a result of the computer modeling, which lacked the fine detail to zoom in on relatively compact urban areas. However, the authors also speculate that wildfire emissions have a greater impact on ozone levels in the countryside than on cities. The reason has to do with chemistry. Cities tend to have more nitrogen dioxide, a pollutant that can, at high levels, reduce the efficiency with which ozone is produced or even destroy ozone."The impact of wildfires on ozone in suburban and rural areas, far from urban sources of pollution, was quite noticeable," says NCAR scientist Christine Wiedinmyer, a co-author of the paper.The paper notes that ozone levels would likely have been even greater except that Santa Ana winds in October blew wildfire plumes over the Pacific Ocean, safely away from populated areas.To measure the impact of the fires on ozone formation, the researchers turned to a pair of computer models developed at NCAR. With the first one, a specialized fire model, they estimated the amount of vegetation burned and resulting emissions of nitrous oxides, sulfur dioxide, and other pollutants. Those results went into a global air chemistry model that simulated the movement of the emissions and evolving chemistry and tracked the resulting formation of ozone as the fire plumes spread downwind.The scientists compared their modeling results with ozone measurements from a network of EPA ground stations at various sites in California. This enabled them to determine both the number of ozone violations and the extent to which the wildfires contributed to those violations. It also enabled them to verify the accuracy of the model.

Ozone Holes

October 7, 2008

https://www.sciencedaily.com/releases/2008/10/081007102853.htm

2008 Ozone Hole Larger Than Last Year

The 2008 ozone hole – a thinning in the ozone layer over Antarctica – is larger both in size and ozone loss than 2007 but is not as large as 2006.

Ozone is a protective atmospheric layer found in about 25 kilometres altitude that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays, which can increase the risk of skin cancer and cataracts and harm marine life.This year the area of the thinned ozone layer over the South Pole reached about 27 million square kilometres, compared to 25 million square kilometres in 2007 and a record ozone hole extension of 29 million square kilometres in 2006, which is about the size of the North American continent.The depletion of ozone is caused by extreme cold temperatures at high altitude and the presence of ozone-destructing gases in the atmosphere such as chlorine and bromine, originating from man-made products like chlorofluorocarbons (CFCs), which were phased out under the 1987 Montreal Protocol but continue to linger in the atmosphere.  Depending on the weather conditions, the size the Antarctic ozone hole varies every year. During the southern hemisphere winter, the atmosphere above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex – the area in which the main chemical ozone destruction occurs. The polar vortex is characterized by very low temperatures leading to the presence of so-called stratospheric clouds (PSCs).As the polar spring arrives in September or October, the combination of returning sunlight and the presence of PSCs leads to a release of highly ozone-reactive chlorine radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.Julian Meyer-Arnek of the German Aerospace Centre (DLR), which monitors the hole annually, explained the impact of regional meteorological conditions on the time and range of the ozone hole by comparing 2007 with 2008."In 2007 a weaker meridional heat transport was responsible for colder temperatures in the stratosphere over the Antarctic, leading to an intensified formation of PSCs in the stratosphere," Meyer-Arnek said. "Therefore, we saw a fast ozone hole formation in the beginning of September 2007.""In 2008 a stronger-than-usual meridional heat transport caused warmer temperatures in the Antarctic stratosphere than usual, reducing the formation of PSCs. Consequently, the conversion of chemically inactive halogens into ozone-destroying substances was reduced. As a result in the beginning of September 2008, the ozone hole area was slightly smaller than average," he continued."Since the polar vortex remained undisturbed for a long period, the 2008 ozone hole became one of the largest ever observed."Minimum values of the ozone layer of about 120 Dobson Units are observed this year compared to around 100 Dobson Units in 2006. A Dobson Unit is a unit of measurement that describes the thickness of the ozone layer in a column directly above the location of measurement.DLR’s analysis is based upon the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) atmospheric sensor onboard ESA’s Envisat, the Global Ozone Monitoring Experiment (GOME) aboard ESA’s ERS-2 and its follow-on instrument GOME-2 aboard EUMETSAT’s MetOp.Scientists say that since the size and precise time of the ozone hole is dependent on the year-to-year variability in temperature and atmospheric dynamics, the detection of signs of ozone recovery is difficult."In order to detect these signs of recovery, a continuous monitoring of the global ozone layer and in particular of the Antarctic ozone hole is crucial," Meyer-Arnek said.In order to train the next generation of atmospheric scientists to continue the monitoring, students at ESA’s Advanced Atmospheric Training Course, held 15–20 September at University of Oxford, UK, were given the task of analysing this year’s ozone hole with Envisat sensors.Studying the Envisat data, the students’ findings were in line with atmospheric scientists that the south polar vortex was more concentric in 2008 than in 2007, leading to a relatively late onset of ozone depletion, and that the size of this year’s hole is similar to previous years."This exercise led us to realise that although many questions have been answered and much has been learned about the stratospheric chemistry and atmospheric dynamics driving ozone hole behaviour, many new questions must be raised especially concerning ozone hole recovery," said Deborah C Stein Zweers, a post-doc satellite researcher from the Royal Netherlands Meteorological Institute (KNMI) who attended the course."We want to know when the ozone hole will recover, how its recovery will be complicated by an environment with increasing greenhouse gases and how atmospheric dynamics will shape future ozone holes. These and many other questions will attract the attention of our generation of scientists for the next several decades."

Ozone Holes

October 7, 2008

https://www.sciencedaily.com/releases/2008/10/081006102537.htm

Air Pollution May Increase Risk Of Appendicitis

Could there be a link between high levels of air pollution and the risk of appendicitis? New research presented at the 73rd Annual Scientific Meeting of the American College of Gastroenterology in Orlando, suggests a novel connection.

"Adult onset appendicitis is a common condition whose cause is unclear and almost universally requires surgery," explained Dr. Gilaad G. Kaplan of the University of Calgary.Dr. Kaplan and his colleagues identified more than 5,000 adults who were hospitalized for appendicitis in Calgary between 1999 and 2006. The team used data from Environment Canada's National Air Pollution Surveillance (NAPS) monitors that collect hourly levels of ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, and particulate matter of varying sizes. Regression analysis was used to evaluate whether short-term daily changes in air pollution levels were related to the development of appendicitis.When researchers compared the 5-day average of ozone concentrations prior to admission to the hospital, patients were approximately 15 percent more likely to be hospitalized for appendicitis on days of highest ozone concentrations compared to days of lowest ozone concentrations. Similar findings were seen for sulfur dioxide, nitrogen dioxide, and particulate matter, though with lower effect. Notably, the effect of air pollution was strongest during the summer months, when people were more likely to be outside.Exposure to air pollutants, particularly ozone, was associated with a modest increased risk of developing appendicitis. Previous studies have shown that air pollution may promote other disease states through inflammation, and this may be the mechanism by which air pollution increases the risk of appendicitis."If the relationship between air pollution and appendicitis is confirmed, then improving air quality may prevent the occurrence of appendicitis in some individuals," said Dr. Kaplan.

Ozone Holes

September 21, 2008

https://www.sciencedaily.com/releases/2008/09/080918170628.htm

Estrogen 'Flooding Our Rivers,' Montreal Study Finds

The Montreal water treatment plant dumps 90 times the critical amount of certain estrogen products into the river. It only takes one nanogram (ng) of steroids per liter of water to disrupt the endocrinal system of fish and decrease their fertility.

These are the findings of Liza Viglino, postdoctoral student at the Université de Montréal's Department of Chemistry, at the NSERC Industrial Research Chair in Drinking Water Treatment and Distribution, who is under the supervision of Professors Sébastien Sauvé and Michèle Prévost.The presence and effects of estrogen residues on aquatic wildlife are well documented. However, this research is unique because it didn't only consider natural hormones and those used in oral contraceptives – it also included products used in hormone therapy that is prescribed to menopausal women. Data indicates that 128 million contraceptive pills and 107 million doses of hormone therapy are consumed every year in Quebec.Water samples were taken in five different spots: the Mille-Îles river, the St. Lawrence River, the two water collectors entering the Montreal treatment plant and at the exit of the plant.The only compound detected in the St. Lawrence River was estradiol, a natural hormone. The water still contained 90 ng of estradiol per liter after being treated. "If other products weren't detected it doesn't mean they aren't present," says Viglino. "Our method doesn't detect amounts lower than 7 ng per liter."According to Professor Sauvé, ozone treatments could eliminate these hormonal compounds. He also stresses that 80 to 90 percent of antidepressants remain in the water after treatment. These molecules can have a variety of effects on aquatic wildlife. Again, ozone treatment could destroy these molecules.

Ozone Holes

August 26, 2008

https://www.sciencedaily.com/releases/2008/08/080822102344.htm

Even Seaweeds Get Sunburned

It is red, it burns and itches: a sunburn on our skin. However, too much sun is not only bad for humans. Many plants react sensitively to an increased dose of ultraviolet radiation, too. Yet they are dependent on sunlight. With the help of pigments absorbing solar energy and light, plants produce their vitally important building blocks by means of photosynthesis.

However, this has its limits: too much sun means an over-abundance of energy and thus the destruction of the sensitive pigments. The result are black spots, pale leaves and rotten parts.Since algae cannot apply sun lotion like we do, they develop their own strategies to protect from the sun: "A species of red algae, for instance, produces under increased ultraviolet radiation less red light-harvesting proteins, thus decreasing the absorption of radiation. The typical red colour of the alga fades and the plant gets white tips.," explains Prof. Dr. Christian Wiencke, marine biologist at the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association. "The algae additionally produce substances which react similar to melanin in human skins: mycosporin amino acids (MAA)." Melanin absorbs ultraviolet radiation and thus protects the human skin – at the same time, it gives a natural suntan.The ozone layer usually absorbs the major part of the hard and harmful solar ultraviolet radiation of short wavelength. However, because of stratospheric ozone depletion, these dangerous rays increasingly penetrate to the earth's surface and therefore also to the seawater.Extensive biological experiments are presently conducted on this complex of problems at the German French Research Base AWIPEV on Spitsbergen. "We examine the harmful effects of ultraviolet radiation on algae and their protective mechanisms," says Wiencke. The ultraviolet radiation particularly harms the algae's photosynthesis and their hereditary material. These organisms usually react with a decreased rate of growth or a reduction of reproductive success.The spores and germ cells of the algae which drift through the water as unicellular organisms are particularly sensitive. Even small ultraviolet doses are damaging and inhibit their germination. "Our investigations show that the distribution of certain species of brown algae is inhibited by the climate of ultraviolet radiation. The algae are displaced into deeper water layers if ultraviolet radiation increases."The research conditions on Spitsbergen are optimal for Wiencke and his colleagues: "We want to observe the development of marine coastal ecosystems in the face of global climate change. Not only an increased ultraviolet radiation plays a decisive role, but also the water temperature which has been increased by the greenhouse effect. This increase in temperature can particularly be felt on Spitsbergen, in the Atlantic sector of the Arctic."

Ozone Holes

July 20, 2008

https://www.sciencedaily.com/releases/2008/07/080714151427.htm

Solar Cooling Becomes A New Air-conditioning System

Scientists from the Universidad Carlos III of Madrid (UC3M) and the Consejo Superior de Investigaciones Científicas (CSIC) have developed an environmentally friendly cooling technology that does not harm the ozone layer. This is achieved by using solar energy and therefore reducing the use of greenhouse gases.

A research team has designed and built an absorption chiller capable of using solar and residual heat as an energy source to drive the cooling system. The technology used in this machine, which looks like an ordinary air-conditioning system, minimises its environmental impact by combining the use of a lithium bromide solution, which does not damage the ozone layer or increase the greenhouse effect, with a reduction in the use of water by the machine.The team, managed by Professor Marcelo Izquierdo from the Department of Thermal Engineering and Fluid Mechanics of the UC3M, who is also a researcher at the Instituto de Ciencias de la Construcción Eduardo Torroja (IETCC) of the CSIC, is building a solar cooling system that unlike the existing machines on the market, uses an improved absorption mechanism capable of producing cold water at a range of temperatures from 7º C to 18º C when the exterior temperature ranges from 33º C to 43º C.Professor Marcelo Izquierdo states that the conclusions reached by a study with a commercial air condensed absorption machine prove that given an outside temperature ranging from 28ºC and 34ºC, the machine can produce cold water at a range of 12 to 16ºC, with a source temperature at the generator between 80ºC to 95ºC. Under these conditions, the cold water produced can be used for climate control applications in houses by combining it with a water-to-air heat exchanger (fan coil).Quoting Raquel Lizarte, a researcher at the Department of Thermal Engineering and Fluid Mechanics of the UC3M, “There are few absorption machines at a commercial level that are adapted for residential use”, and since it is very hard to go without climate control, it is important to find a cooling technology that has minimal environmental impact. “The machine that we're studying produces enough cold water to cool down a room of 40 m2 of floor area and with a volume of 120 m3”, she states.In 2007, 191 countries were involved in the Montreal protocol; a signed agreement to avoid the use of ozone depleting substances such as the HCFC refrigerants used in the air-conditioning industry as well as to set a limit such that by the year 2010 the energy consumption should be just 25% of the level that was allowed in 1996. Also, by the year 2020 all the HCFC refrigerants used in developed countries will have to be replaced with substitutes. This protocol makes research into this kind of technology extremely important for the near future.The study has been published in the current edition of the magazine Applied Thermal Engineering under the title: ‘Air conditioning using an air-cooled single effect lithium bromide absorption chiller: Results of a trial conducted in Madrid in August 2005’. In this investigation scientists from the Universidad Carlos III of Madrid and Universidad Nacional de Educación a Distancia have collaborated under the coordination of the Instituto de Ciencias de la Construcción Eduardo Torroja-CSIC.

Ozone Holes

June 26, 2008

https://www.sciencedaily.com/releases/2008/06/080625140656.htm

Destruction Of Greenhouse Gases Over Tropical Atlantic May Ease Global Warming

Large amounts of ozone -- around 50% more than predicted by the world's state-of-the-art climate models -- are being destroyed in the lower atmosphere over the tropical Atlantic Ocean. This startling discovery was made by a team of scientists from the UK's National Centre for Atmospheric Science and Universities of York and Leeds. It has particular significance because ozone in the lower atmosphere acts as a greenhouse gas and its destruction also leads to the removal of the third most abundant greenhouse gas; methane.

The findings come after analysing the first year of measurements from the new Cape Verde Atmospheric Observatory, recently set up by British, German and Cape Verdean scientists on the island of São Vicente in the tropical Atlantic. Alerted by these Observatory data, the scientists flew a research aircraft up into the atmosphere to make ozone measurements at different heights and more widely across the tropical Atlantic. The results mirrored those made at the Observatory, indicating major ozone loss in this remote area.So, what's causing this loss? Instruments developed at the University of Leeds, and stationed at the Observatory, detected the presence of the chemicals bromine and iodine oxide over the ocean for this region. These chemicals, produced by sea spray and emissions from phytoplankton (microscopic plants in the ocean), attack the ozone, breaking it down. As the ozone is destroyed, a chemical is produced that attacks and destroys the greenhouse gas methane. Up until now it has been impossible to monitor the atmosphere of this remote region over time because of its physical inaccessibility. Including this new chemistry in climate models will provide far more accurate estimates of ozone and methane in the atmosphere and improve future climate predictions.Professor Alastair Lewis, Director of Atmospheric Composition at the National Centre for Atmospheric Science and a lead scientist in this study, said: "At the moment this is a good news story -- more ozone and methane being destroyed than we previously thought - but the tropical Atlantic cannot be taken for granted as a permanent 'sink' for ozone. The composition of the atmosphere is in fine balance here- it will only take a small increase in nitrogen oxides from fossil fuel combustion, carried here from Europe, West Africa or North America on the trade winds, to tip the balance from a sink to a source of ozone"Professor John Plane, University of Leeds said: "This study provides a sharp reminder that to understand how the atmosphere really works, measurement and experiment are irreplaceable. The production of iodine and bromine mid-ocean implies that destruction of ozone over the oceans could be global".Dr Lucy Carpenter, University of York and UK co-ordinator of the Observatory added: "This observatory is a terrific facility that will enable us to keep an eye on the chemical balance of the atmosphere and feed this information into global climate models to greatly improve predictions for this region in the future".

Ozone Holes