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April 15, 2021 | https://www.sciencedaily.com/releases/2021/04/210415114202.htm | Impacts of coronavirus lockdowns: New study collects data on pollutants in the atmosphere | One consequence of the coronavirus pandemic has been global restrictions on mobility. This, in turn, has had an effect on pollution levels in the atmosphere. Researchers from across the world are using this unique opportunity to take measurements, collect data, and publish studies. An international team led by Forschungszentrum Jülich's Institute of Climate and Energy Research -- Troposphere has now published a comprehensive review providing an overview of results up to September 2020. The study also has its own dedicated website, where additional measurement data can be added to supplement and refine existing research results. At the same time, this collection of data allows scientifically substantiated predictions to be made about the pollution levels of future mobility scenarios. | The meta-analysis was coordinated by Prof. Astrid Kiendler-Scharr, director at Jülich's Institute of Climate and Energy Research -- Troposphere. The analysis covers the measurement data of around 200 studies from the first seven months following the onset of the pandemic. It focuses on the following air pollutants: nitrogen dioxide, particulate matter, ozone, ammonia, sulfur dioxide, black carbon, volatile organic compounds (VOCs), and carbon monoxide. A third of the studies take into account the prevailing meteorological situation when calculating the influence of lockdowns on the air composition. The Government Stringency Index (SI) -- summarizing the severity of local shutdown measures in a number that can be compared at international level -- acted as a reference value.A key finding of the analysis is that lockdowns, which have the sole aim of slowing down the infection rate, are also reducing the global pollution of the atmosphere with nitrogen dioxide and particulate matter -- the higher the SI, the greater this impact. However, this only applies to pollutants that primarily have an anthropogenic origin, i.e. are directly emitted by humans, especially in the field of mobility. In contrast, ozone levels increased. This increase was a result of atmospheric chemical processes caused by reduced nitrogen oxide levels in the air.The study also highlights current gaps in the data collection and the need for further research. The authors are therefore of the opinion that the period of analysis should be extended to cover the entire year of 2020. The scientists place a particular emphasis on hydrocarbons, which have so far only been examined sporadically in studies, and on extended analyses looking at the impact of emission changes on the climate.An important addition to the meta-analysis is a database that can be accessed via a website (COVID-19 Air Quality Data Collection -- The website also invites scientists to present data from their new studies and to thus become part of the reference system. It therefore acts as a "living version," with the presentation of collected results being constantly refined. Similarly, there are plans to further develop the data collection to include measurement results and the analysis of other pollutants that are not part of the current canon, for example hydrocarbons.The important data could also form the basis for better assessments of the impacts on atmospheric chemistry in future scenarios. This includes a considerable, long-term reduction in pollution levels for a comprehensive transition to electromobility. | Ozone Holes | 2,021 |
April 5, 2021 | https://www.sciencedaily.com/releases/2021/04/210405123308.htm | Ozone pollution harms maize crops, study finds | Although stratospheric ozone protects us by filtering out the sun's ultraviolet radiation, tropospheric ozone is a harmful pollutant. A new study has shown that ozone in the lower layers of the atmosphere decreases crop yields in maize and changes the types of chemicals that are found inside the leaves. | Ozone is formed when nitrous oxide, released from industries and tail pipes of cars, is broken down by sunlight and chemically reacts to form ozone. Researchers at the University of Illinois Urbana-Champaign have been studying the effects of ozone pollution on crops for over 20 years at a unique facility where crops can be grown under real-world farm field conditions but with increased concentrations of ozone pollution."Ozone pollution is higher in the northern hemisphere, and peaks in the warmer, summer months. High concentrations of ozone pollution overlap temporally and spatially with crop growth, so it is important to study how the high ozone concentrations affect crop yields," said Jessica Wedow, a former PhD student in the Ainsworth lab.The researchers looked at three types of maize: two inbred lines B73 and Mo17, and the hybrid cross B73 × Mo17. Surprisingly, they found that chronic ozone stress caused a 25% decrease in yield in the hybrid crops while the inbred plants remained unaffected. The hybrid plants also aged faster than the inbred crops.To understand why B73 × Mo17 was affected, the researchers measured the chemical composition of the leaves. "The inbred plants did not respond to ozone. On the other hand, the hybrid plants produced more ??tocopherol and phytosterols, which help quench reactive oxygen molecules and stabilize the chloroplast membranes," Wedow said. These results suggest that the since the hybrid maize is more sensitive to ozone exposure, they may be producing more chemicals that deal with the consequences of chronic ozone stress."This study provides clues to improve maize tolerance to ozone pollution," said Lisa Ainsworth (GEGC), the Research Leader of the USDA ARS Global Change and Photosynthesis Research Unit. The group is currently studying whether these responses are consistent across other important grasses, including those used for bioenergy. | Ozone Holes | 2,021 |
December 2, 2020 | https://www.sciencedaily.com/releases/2020/12/201202114540.htm | Ozone breaks down THC deposited on surfaces from thirdhand cannabis smoke | Second- and thirdhand tobacco smoke have received lots of attention, but much less is known about the compounds deposited on surfaces from cannabis smoke. Now, researchers reporting in ACS' | Smoking emits reactive chemicals that remain in the air (so-called secondhand smoke) or deposit onto surfaces, including walls, windows, clothing and upholstery (thirdhand smoke). Unlike the secondhand variety, thirdhand smoke lingers long after a person stops smoking. Nicotine is semi-volatile and reacts with other chemicals on surfaces, producing new compounds that, if volatile, can also become airborne. Because cannabis smoke is chemically distinct from tobacco smoke, Aaron Wylie and Jonathan Abbatt wanted to characterize the compounds formed when THC, by itself or in cannabis smoke, on surfaces reacts with ozone in the air.The researchers coated glass and cotton cloth, to simulate windows and clothing, with a THC solution. Then, they exposed the surfaces to concentrations of ozone that could exist in indoor air. In their analysis, they found that over time, the amount of THC on glass and cotton decreased, while the quantities of three THC oxidation products increased. In other experiments, the team used a smoking machine to deposit cannabis smoke onto cotton. Upon exposure to ozone, the same three compounds formed at roughly the same rate as observed for the THC-coated cloth. Because of the low volatility of THC and its oxidation products, the compounds are unlikely to be emitted to the air where they could be inhaled in as large amounts as nicotine, the researchers say. They say that somebody could still be exposed to THC and its derivatives, whose health effects are unknown, if they, for example, lick their fingers after touching a surface contaminated by cannabis smoke.The authors acknowledge funding from the Chemistry of Indoor Environments program at the Alfred P. Sloan Foundation. | Ozone Holes | 2,020 |
November 23, 2020 | https://www.sciencedaily.com/releases/2020/11/201123120730.htm | Shift in atmospheric rivers could affect Antarctic sea ice, glaciers | Weather systems responsible for transporting moisture from the tropics to temperate regions in the Southern Hemisphere have been gradually shifting toward the South Pole for the past 40 years, a trend which could lead to increased rates of ice melt in Antarctica, according to new research. | Atmospheric rivers are long, narrow jets of air that carry huge amounts of water vapor from the tropics to Earth's continents and polar regions. The new study finds atmospheric rivers in the Southern Hemisphere are shifting due in part to ozone depletion, greenhouse gas emissions and natural variations in sea surface temperature.This shift of atmospheric rivers may affect moisture and heat transported into Antarctica, said Weiming Ma, an atmospheric scientist at UCLA and lead author of the new study published in the AGU journal "The most important implication of our finding is that due to this shift, more atmospheric rivers are expected to make landfall over Antarctica, which will have effects on the surrounding sea ice and glaciers on the continent," Ma said.Atmospheric rivers form when warm, turbulent air from the tropics encounter cold fronts in mid-latitude regions. The narrow band between these two competing air masses grows thick with condensed water vapor as temperatures drop in the region of saturated air.Sometimes measuring thousands of kilometers in length, these cloud systems can contribute up to 60% of the annual precipitation in some regions, such as California, Chile and western Europe.In the past, scientists have used simulations to predict the future occurrence of atmospheric rivers over western Europe, showing that these weather patterns are likely to become more common under a warming climate. However, since their direction and movement are determined in large part by Earth's jet streams, and as the westerly jet is expected to shift toward the North Pole in future climate models, researchers predict that atmospheric rivers will likely move poleward as well.But the new study found atmospheric rivers in the Southern Hemisphere have already been following this trend, steadily creeping toward the South Pole for at least the last four decades. Using simulations based on multiple models and datasets spanning back to 1979, the researchers looked for broad trends and potential mechanisms that might explain observed patterns.According to modeling results from the new study, at least part of the observed trend can be explained by increases in greenhouse gas emissions and ozone depletion over Antarctica and their corresponding effect on temperature gradients between the equator and South Pole; however, the shift also appears to be driven by natural, long-term changes in sea surface temperatures."We found evidence for cooling over the equatorial Pacific and the Southern Ocean, which is caused by a pattern called the inter-decadal Pacific Oscillation," said Ma. "This is a natural pattern that takes place over multiple decades and one that isn't driven by human activity."These cooler patterns in sea surface temperature pull the westerly jet stream further south, pushing atmospheric rivers along with them. It's unclear exactly how this might affect rain and snowfall patterns over South America, but it seems likely that portions of Antarctica will experience increased rates of ice melt as a result, according to the researchers."Global sea level change depends critically on the fate of the Antarctic ice sheet, and that ice is impacted by how many atmospheric rivers hit Antarctica and how strong they are," said Marty Ralph, the director for the Center for Western Weather and Water Extremes at the Scripps Institution of Oceanography, who was not involved in the new study.While atmospheric rivers over East Antarctica have been associated with increased snowfall accumulation in some years, they seem to have the opposite effect on the other side of the continent. According to research published in 2019 that used a similar dataset, an average of only 12 atmospheric rivers a year make their way across the western portion of Antarctica, yet they contribute up to 40% of the summer ice melt in some areas and appear to be responsible for the majority of ice melt in winter and in high-elevation glaciers.Large ice melts in West Antarctica are still fairly rare, occurring only a few times each decade. However, scientists warn that increasing temperatures due to global climate warming and the shifting occurrence of atmospheric rivers in the southern hemisphere will likely cause the frequency and severity of those melting events to increase in the near future. | Ozone Holes | 2,020 |
September 24, 2020 | https://www.sciencedaily.com/releases/2020/09/200924082709.htm | Climate pledges 'like tackling COVID-19 without social distancing' | Current global pledges to tackle climate change are the equivalent of declaring a pandemic without a plan for social distancing, researchers say. | In the Paris Agreement, nations agreed to limit global warming to "well below 2°C."But University of Exeter scientists say governments are engaged in "climate hypocrisy" by publicly supporting the agreement while subsidising the fossil fuel industry, destroying forests and pursuing other harmful policies.Writing in the journal The call comes as world leaders including UK Prime Minister Boris Johnson discuss climate action and a "sustainable recovery" from the pandemic at the UN General Assembly."Restoring the ozone layer and minimising the COVID-19 pandemic both required governments to enact specific legislation to address the precise causes of these problems," said Professor Mark Baldwin, of Exeter's Global Systems Institute (GSI)."By contrast, Paris Agreement commitments are the equivalent of intending to restore the ozone layer without a plan for eliminating ozone-depleting substances, or intending to end the COVID-19 pandemic without a plan for social distancing to reduce the spread of the virus."We know the climate crisis is caused mainly by fossil fuels."Current climate and energy policies are therefore nonsensical because they condemn greenhouse gas emissions by individuals while promoting fossil fuel production."Today we have governments publicly supporting the Paris Agreement, but simultaneously opening new coal mines, destroying forests, supporting fracking, subsidising the fossil fuel industry and supporting fossil fuel projects in the developing world."Professor Tim Lenton, director of the GSI, said: "The fundamental reason we are not solving the climate crisis is not a lack of green energy solutions -- it is that many governments continue energy strategies that prioritise fossil fuels."These entrenched energy policies subsidise the discovery, extraction, transport and sale of fossil fuels, with the aim of ensuring a cheap, plentiful, steady supply of fossil energy into the future."Some governments are introducing policies to reduce demand for fossil fuels and shift to green energy sources, but these policies are not enough."Green energy is not yet replacing fossil fuels -- it is merely augmenting it. Energy from both fossil fuels and green sources is increasing."Individual behaviour choices -- such as diets and modes of travel -- are important, but more fundamental is to replace the supply of fossil fuels with green energy."The researchers call for a "comprehensive global plan" to solve the climate crisis.They make seven recommendations:Professor Baldwin added: "To bring about real change, we must address complex issues involving politics, fake news, human behaviour, government subsidies, taxes, international trade agreements, human rights, lobbying by the fossil fuel industry, and disinformation campaigns." | Ozone Holes | 2,020 |
September 21, 2020 | https://www.sciencedaily.com/releases/2020/09/200921130640.htm | Unexpected wildfire emission impacts air quality worldwide | In lab studies of wildfire, nitrous acid seems like a minor actor, often underrepresented in atmospheric models. But in the real-world atmosphere, during wildfires, the chemical plays a leading role -- spiking to levels significantly higher than scientists expected, driving increased ozone pollution and harming air quality, according to a new study led by the University of Colorado Boulder and the Belgian Institute for Space Aeronomy. | "We found nitrous acid levels in wildfire plumes worldwide are two to four times higher than expected," said Rainer Volkamer, CIRES Fellow, professor of chemistry at CU Boulder and co-lead author on the Nitrous acid in wildfire smoke is accelerating the formation of an oxidant, the hydroxyl radical or OH. Unexpectedly, nitrous acid was responsible for around 60 percent of OH production in the smoke plumes worldwide, the team estimated -- it is by far the main precursor of OH in fresh fire plumes. The hydroxyl radical, then, can degrade greenhouse gases, and it can also accelerate the chemical production of ozone pollution -- by as much as 7 parts per billion in some places. That's enough to push ozone levels over regulated levels (eg, 70 ppb in the United States)."Fire size and burn conditions in the real world show higher nitrous acid than can currently be explained based on laboratory data, and this added nitrous acid drives faster chemistry to form ozone, oxidants and modifies aerosols in wildfire smoke," Volkamer said.Nitrous acid, while abundant after wildfire, degrades quickly in sunlight, and is thus exceedingly difficult to study globally. So the CU Boulder team worked with European colleagues to combine two sets of data: 1) global measurements from a satellite instrument TROPOMI observed nitrous acid in wildfire plumes around the world, and 2) custom instruments flown on aircraft during a 2018 wildfire study in the Pacific Northwest during the BB-FLUX campaign. Remarkably, the team was able to compare near-simultaneous measurements made within minutes by the satellite looking down on a plume, and the aircraft-based instrument looking up into the same plume from below."Kudos to the pilots and the entire team for dealing actively with this fundamental sampling challenge," Volkamer said. "Simultaneous measurements conducted at different temporal and spatial scales helped us to understand and use what are the first global measurements of nitrous acid by our Belgium colleagues." With the new comparison in hand, Volkamer and his colleagues -- including Nicolas Theys, the study's lead author from BIRA -- could then scrutinize satellite data from a large number of wildfires in all major ecosystems across the planet to assess nitrous acid emissions.The chemical is consistently higher than expected everywhere, but levels differ depending on the landscape. "Nitrous acid emissions relative to other gases involved in ozone formation varied by ecosystem, with the lowest in savannas and grasslands and highest in extratropical evergreen forests," said Kyle Zarzana, chemistry postdoctoral scientist at CU Boulder who led instrument deployment for the aircraft measurements, and coauthor on the new paper."Wildfire smoke contains many trace gases and aerosols that adversely affect visibility and public health over large distances, as we are recently witnessing from fires raging in the Western United States that affect air quality on the East Coast," said Volkamer. "Our findings reveal a chemically very active ingredient of this smoke, and help us to better keep track as photochemistry rapidly modifies emissions downwind." | Ozone Holes | 2,020 |
September 8, 2020 | https://www.sciencedaily.com/releases/2020/09/200908131032.htm | Detecting soil-surface ozone early can help prevent damage to grapes and apples | Farmers and fruit growers are reporting that climate change is leading to increased ozone concentrations on the soil surface in their fields and orchards -- an exposure that can cause irreversible plant damage, reduce crop yields and threaten the food supply, say materials chemists led by Trisha Andrew at the University of Massachusetts Amherst. | Writing in They write, "We selected grapes (Vitis vinifera L.) as our model plant because the fruit yield and fruit quality of grapevines decrease significantly upon exposure to ground level ozone, leading to significant economic losses." Ground-level ozone can be produced by the interaction between the nitrates in fertilizer and the sun, for example.UMass Amherst viniculturist Elsa Petit, who advised the chemistry team, says the sensor tattoo could be especially useful to the grape industry. "With climate change, ozone will increase and this new sensor might be extremely useful to help farmers act before the damage is recognizable by eye," she says. Ground-level ozone can be mitigated by early detection and treating the soil surface with charcoal or zeolite powders.As Andrew explains, her lab, funded by the National Science Foundation, adapted the electrode vapor-deposition method they had developed earlier to coat fabrics for medical sensing devices for a new use -- on living plants. The conducting polymer film, poly(3,4-ethylenedioxytiophene), PEDOT, is just 1 micron thick so it lets sunlight in and does not hurt leaves. Non-metal, carbon-based polymers that act as conducting electrodes are increasingly used in soft materials design since they were invented in the 1970s, she adds."Ours acts like a temporary tattoo on a human," Andrew says. "It doesn't wash away and the polymer's electrical properties don't degrade, even over a long time. We have some tattooed plants in a greenhouse on campus and a year later they are still growing fine, putting out roots and leaves as normal."To test for early ozone damage, she and colleagues use a hand-held impedance spectrometer adapted from human medical practice. When it touches the electrode tattoo, a read-out reports the electrical resistance vs frequency relationship. This voltage value changes in the presence of various factors, including oxidative damage from ozone.Andrew says, "You get a wave-form image; a software program fits the wave so we can extract certain tissue parameters. We can recognize patterns for different kinds of damage. It's consistent and remarkably accurate. If you use it on the same plant over a year, as long as the plant is healthy the signal doesn't really change over that time.""The problem scientifically is that visual ozone damage looks exactly the same as if you watered the plant too little or it got too much sun. This project became intellectually interesting to us when we looked at the ozone signature of our read-outs and it was very different from drought or UV damage. Ozone produces a unique change in the high-frequency electrical impedance and phase signals of leaves."The scientists hope their invention could be used by farmers and fruit growers who could place a few "reporter plants" among crops to periodically monitor soil ozone levels. "It gives you a picture of what is going on in your soil," Andrew suggests. "You can be alerted if the fertilizer level is wrong, for example. This can happen, especially with food crops that need a lot of sun and fertilizer to produce, like melons, grapes and orchard fruits. Some plants are very sensitive to it." | Ozone Holes | 2,020 |
September 4, 2020 | https://www.sciencedaily.com/releases/2020/09/200904101806.htm | Pollination: Air pollution renders flower odors unattractive to moths | A team of researchers from the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Virginia, USA, has studied the impact of high ozone air pollution on the chemical communication between flowers and pollinators. They showed that tobacco hawkmoths lost attraction to the scent of their preferred flowers when that scent had been altered by ozone. This oxidizing pollutant thus disturbs the interaction between a plant and its pollinator, a relationship that has evolved over millions of years. However, when given the chance, hawkmoths quickly learn that an unpleasantly polluted scent may lead to nutritious nectar. | Pollination is a critical ecosystem service, one that is performed mainly by insects. Flowers attract insects using floral scents, which are chemical signals that the pollinators can have an innate preference for. This preference is the result of the co-evolutionary relationship between flowers and their pollinators that has evolved over millions of years.For about 20 years, the term "Anthropocene" has been used in the scientific community to refer to the geological epoch in which humans are responsible for many changes in biological and atmospheric processes. However, until recently, little has been known about the effects of anthropogenic climate change and atmospheric pollution on natural environmental odors that drive chemical communication between organisms.A team of researchers from the Max Planck Institute for Chemical Ecology and the University of Virginia has investigated whether human-driven ozone pollution in the air influences the attraction of a pollinating moth to the scent of one of their favorite flowers. Ozone is an oxidant, a highly reactive chemical and pollutant known to cause respiratory diseases in humans. Now, ozone is also thought to change the floral scents that flowers emit to attract their pollinators.For their experiments, the scientists used the tobacco hawkmoth Manduca sexta. "The hawkmoth Manduca sexta is the perfect model for our study. Although it is highly attracted by flower odors, it also uses its visual system to locate flowers. Flowers that usually attract hawkmoth often share specific compounds in their blend and are visually very conspicuous due to their bright white color," says study leader Markus Knaden, who heads a research group in the Department of Evolutionary Neuroethology at the Max Planck Institute.The research team first determined the exact compositions of the flower odors -- with and without increased ozone content -- and the respective concentrations of individual odor components using gas chromatography. For the ozone-altered odors, the researchers used ozone concentrations that can be measured on hot days in the natural habitat of tobacco hawkmoths. They tested the responses of the moths in behavioral assays in a wind tunnel, allowing the insect to investigate both the original floral odor and to the ozone-altered floral odor."We were surprised, even shocked, that the innate attraction to the odor of tobacco flowers was completely lost in the presence of increased ozone levels," said Knaden, describing what was observed during the experiments.The question remained whether ozone in the air would spoil the appetite of hungry and foraging tobacco hawkmoths, or whether it would prevent insects from finding their food source. Would insects be able to figure out that even polluted flower odors can offer rewards? To answer this question, researchers tested whether tobacco hawkmoths could learn to accept an initially unattractive scent as a food cue if they smelled it while simultaneously being offered a sugar solution reward. The researchers assessed several different ways in which the moth could learn to recognize flowers based on the ozone-altered floral scent. This was critical to relating these experiments to real-world learning. In the real world, a floral scent only becomes ozone-altered as it moves downwind of the flower and mixes with ozone. To see if moths could learn ozone-altered floral scents even when they are decoupled from the sugar reward at the flower, the researchers developed an experiment where the moth had to follow the ozone-altered odor to the flower, but were presented with the original scent at the flower containing the sugar reward."While we anticipated that Manduca sexta could learn new floral scents and hoped that they would be able to learn the polluted floral scent of their host flower, we were amazed to see that Manduca sexta could learn the polluted floral blend in a number of different ways, including learning a polluted scent that was decoupled from a sugar reward. This type of learning, which we were surprised to find in Manduca sexta, could be very important in insects' ability to use learning to cope with their rapidly changing environments," says first author Brynn Cook from the University of Virginia. What is especially noteworthy and pertinent about this kind of responsiveness to a changing environment is that it occurs in real time and not over evolutionary timescales.Although the study shows that tobacco hawkmoths can learn to rely on ozone-altered and initially unattractive plumes to recognize their flowers, air pollution still poses a serious risk to pollination and pollinators. "Learning may be key to insects recognizing their host plants in polluted environments, but one of the major questions remaining from our study is whether pollinators will be able to find their flowers in the first place. Without initially recognizing smells, will pollinators only have visual cues to help them locate host flowers in order to learn the pollution-altered floral scent? Another important aspect to consider is that other pollinators may not have the same facility to learn new smells that Manduca sexta has. Specialist pollinators, for instance, may not have that flexibility in learning. Our study is just a starting point. Field studies are going to be critical to understanding which flowers and insects are most affected by which pollutants, and likely why," says Cook.Air pollution and climate change have far-reaching consequences for our ecosystem; by no means have all of these been studied and understood. For example, we still know little about the impact of atmospheric changes on the chemical communication between plants and insects. Not only are plant odors altered, but also the sex pheromone female insects use to attract males. Atmospheric changes have the potential to cause alterations in pheromones that could lead to mating failure. Insect mortality has risen dramatically in recent years, and researchers worldwide are searching for the causes. Since 2020, the Max Planck Center next Generation Insect Chemical Ecology, a cooperation between the Max Planck Society and two Swedish universities in which the Max Planck Institute for Chemical Ecology and the co-authors of the study, Bill Hansson and Markus Knaden, play a major role, has been dedicated to this field of research. | Ozone Holes | 2,020 |
August 27, 2020 | https://www.sciencedaily.com/releases/2020/08/200827105911.htm | Forest emissions: A chiral surprise in the rainforest | Forests such as the Amazon rainforest emit huge amounts of biogenic volatile organic compounds (BVOC) into the atmosphere. These compounds impact the physical and chemical properties of the atmosphere and also our climate. The molecules react rapidly with ambient OH radicals and ozone, thereby influencing the oxidation capacity of the atmosphere for pollutants such as carbon monoxide and greenhouse gases such as methane. Furthermore, BVOC are precursors to secondary organic aerosols, which affect the Earth's radiative budget. Many BVOCs such as a-pinene are chiral. This means that they exist in two non-superimposable mirror image forms just like our left and right hands. Scientists speak of enantiomers, or plus and minus forms. However, all physical properties such as their boiling point, mass and their reaction rate with atmospheric oxidizing agents like OH and ozone are identical. | Despite the chemical similarity of these chiral pairs, insects and plants can distinguish enantiomeric forms of pheromones and phytochemicals, although little attention has been paid to the mixing ratio of the two separated forms in forests. Previous measurements reported minus α-pinene to be the dominant chiral molecule of the tropical forest. Scientists from the Max Planck Institute for Chemistry, the Johannes Gutenberg-University Mainz and from Brazil have now made a surprising discovery: from the 325-meter-high measuring tower in the Amazon rainforest, they were able to show that the ratio of the α-pinene enantiomers varies in the vertical by a factor of ten. The team around the Max Planck researcher Nora Zannoni was also able to demonstrate that the concentrations are altitude-dependent and vary with the time of day and in both wet and dry seasons.While plus-α-pinene dominates at 40 meters anytime and at 80 meters during the night, the minus form predominates at 80 meters during the day and at all other higher heights anytime. The team also observed that the minus α-pinene concentration depends on temperature at 80 meters while plus α-pinene does not. "The photosynthetic activity of the vegetation depends on temperature and stomatal opening. It thus drives the emissions of minus α-pinene, demonstrating that leaves are the main source of emission of this isomer, and that the two isomers are released from leaves through different pathways," says Zannoni, who is first author of a study recently published in the science magazine During the dry season, the chiral ratio of the two forms reverses at 80 meters. "This indicates a strong, uncharacterized source of plus α-pinene in the canopy," says Jonathan Williams, group leader at the institute in Mainz and last author of the study. Since the researchers couldrule out atmospheric sinks such as the chiral-selective degradation of pinene by OH radicals and ozone or deposition onto aerosols as well as the influence of wind direction and sunlight, they instead suspect that insect stresses such as herbivores feeding and termites emissions are responsible for the plus α-pinene higher values. In order to test a possible impact of insects the researchers conducted additional measurements above termite nests which confirmed that such emissions can overturn the ambient chiral ratio of α-pinene. As termite populations are expected to increase significantly in the future with continued deforestation and climate warming, their influence needs to be considered in forest emission models and forest signaling."We also know that plants can release large amounts of plus α-pinene when injured or eaten," Williams adds. This is supported by measurements of volatile compounds associated with leaf wounding that even revealed when the herbivores were most active. The atmospheric chemists Zannoni and Williams conclude that they need to rethink how canopy emissions of volatile organic compounds are simulated, and take the whole ecosystem into account.The research was co-financed by the H2020 project "ULTRACHIRAL" of the European Union. | Ozone Holes | 2,020 |
August 26, 2020 | https://www.sciencedaily.com/releases/2020/08/200826083036.htm | Experts reveal major holes in international ozone treaty | A new paper, co-authored by a University of Sussex scientist, has revealed major holes in an international treaty designed to help repair the ozone layer, putting human health at risk and affecting climate. | Evidence amassed by scientists in the 1970s and 1980s showed that the depletion of the ozone layer in the stratosphere was one of the first truly global threats to humanity.Chemicals produced through economic activity were slowly drifting to the upper atmosphere where they were destroying the ozone layer, which plays an indispensable role in protecting humanity and ecosystems by absorbing harmful ultraviolet radiation from the sun.In 1987, countries signed up to a treaty to take reparative action, known as the 'Montreal Protocol on Substances that Deplete the Ozone Layer, which was eventually ratified by all 197 UN member states.'But in a paper published today in Professor Joseph Alcamo, Director of the Sussex Sustainability Research Programme and former Chief Scientist at UNEP, said: "The Montreal Protocol and its amendments have no doubt been an effective worldwide effort to control the toughest substances depleting the ozone. But our paper shows that the treaty has developed too many gaps to fully repair the ozone layer. It's time to plug the holes in the ozone hole treaty."Professor Alcamo, along with lead author Professor Susan Solomon of Massachusetts Institute of Technology (MIT) and co-author Professor A. R. Ravishankara of Colorado State University, have identified several 'gaps' which consist of ozone depleting substances not covered in the treaty.These include:The authors have called for a range of solutions to plug the gaps including:The ozone layer absorbs harmful ultraviolet radiation from the sun but this protective layer is slowly destroyed by industrial gases that slowly drift up from the earth's surface including CFCs (chlorofluorocarbons) contained in refrigerants, foaming agents and, earlier, propellants in aerosol sprays.Discovery of the 'ozone hole' above high latitudes in the 1980s provided final evidence of the importance of ozone depletion.By 1985, countries had signed the Vienna Convention, which pledged to reduce CFCs and other ozone-depleting substances. Two years later, they signed the Montreal Protocol that laid out a plan of action.During his time as the first Chief Scientist of UNEP, which hosts the Secretariat of the Montreal Protocol, Professor Alcamo coordinated groups of scientists in producing policy-oriented reports that addressed emerging ozone depletion issues.UNEP reports that 98% of the chemicals targeted for removal in the Montreal Protocol had been phased out by 2009, avoiding hundreds of millions of cases of skin cancer and tens of millions of cases of cataracts. However, this new paper shows that some important sources were not targeted by the Protocol -- and urgently need to be now.Professor Alcamo said: "Since most ozone-depleting gases and their current substitutes are also potent greenhouse gases, it's time to use the Montreal Protocol to draw down these gases even faster to help avoid dangerous global warming."We won't be able to reach the global Sustainable Development Goals by 2030 without closing the gaps in the ozone treaty. It's hard to imagine, for example, how the global health and climate goals could be reached without drastically drawing down all ozone-depleting gases and their substitutes. If we fail, humanity will have to face a higher risk of skin cancers and more rapid climate change." | Ozone Holes | 2,020 |
August 21, 2020 | https://www.sciencedaily.com/releases/2020/08/200821141311.htm | Ozone across northern hemisphere increased over past 20 years | In a first-ever study using ozone data collected by commercial aircraft, researchers from the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder found that levels of the pollutant in the lowest part of Earth's atmosphere have increased across the Northern Hemisphere over the past 20 years. That's even as tighter controls on emissions of ozone precursors have lowered ground-level ozone in some places, including North America and Europe. | Tropospheric ozone -- ozone between Earth's surface and 12 to 15 kilometers above Earth -- is a greenhouse gas and air pollutant that, at high levels, can harm people's lungs and damage plants.In a study published today in the journal Gaudel and her co-authors, CIRES scientists in NOAA and international colleagues, also found the most striking increases in areas where ozone levels were once lowest: Malaysia/Indonesia, Southeast Asia and India, for example. Those regions had very low ozone values between 1994-2004, and very high levels in recent years, between 2011-2016.Previous studies could not draw firm conclusions on Northern Hemisphere ozone trends, according to Gaudel, because there are too few long-term monitoring locations and because new satellites with near-global coverage have provided conflicting results on ozone trends.So the researchers turned to aircraft data from Europe's In-Service Aircraft for the Global Observing System (IAGOS) program. "Since 1994, IAGOS has measured ozone worldwide using the same instrument on every plane, giving us consistent measurements over time and space from Earth's surface to the upper troposphere," Gaudel said. Between 1994 and 2016, commercial aircraft captured 34,600 ozone profiles, or about four profiles each day.Gaudel and her colleagues used these measurements to calculate changes in tropospheric ozone from the mid-1990s to 2016 above 11 regions in the Northern Hemisphere. They found an overall increase in ozone in all regions where they looked, including four in the mid-latitudes, two in the subtropics, two in the tropics and three equatorial regions. On average, median ozone values had increased by 5% per decade.In the so-called "lower troposphere," which is closer to Earth's surface, ozone has decreased above some mid-latitude regions, including Europe and the United States, where ozone precursor emissions have decreased. The researchers found those reductions were offset by increases higher in the troposphere -- with the net result being an overall ozone increase from the surface to 12 km.To understand what was causing the observed ozone changes, the researchers looked at the emissions inventories of one of the main ozone precursors -- nitrogen oxides (NOx) -- used as input for the global chemistry transport model MERRA-2 GMI, which reproduces accurately the IAGOS measurements. The model showed that increased anthropogenic emissions in the tropics were likely driving the observed increase of ozone in the Northern Hemisphere.Next, Gaudel wants to take a closer look at ozone in the tropics. Africa may be emerging as a global hotspot for air pollution precursors, for example, and IAGOS data will let her dig deeper into that continent's role in recent trends. She'll also compare tropical ozone measurements from IAGOS, taken above polluted regions, with measurements from the NASA Atmospheric Tomography (ATom) field campaign, which measured trace gases and aerosol particles in more remote, less polluted regions including the tropics. And she'll look at measurements from TROPOMI, an instrument on board a European Space Agency satellite gathering information on atmospheric composition."We want to understand the variability of ozone and its precursors and the impact of polluted regions on remote regions," Gaudel said. "So we're using the best tools we have, including IAGOS, ATom data and TROPOMI data, to get profiles and columns of ozone and its precursors from different kinds of human activities and natural sources." | Ozone Holes | 2,020 |
August 18, 2020 | https://www.sciencedaily.com/releases/2020/08/200818142104.htm | Exploding stars may have caused mass extinction on Earth, study shows | Imagine reading by the light of an exploded star, brighter than a full moon -- it might be fun to think about, but this scene is the prelude to a disaster when the radiation devastates life as we know it. Killer cosmic rays from nearby supernovae could be the culprit behind at least one mass extinction event, researchers said, and finding certain radioactive isotopes in Earth's rock record could confirm this scenario. | A new study led by University of Illinois, Urbana-Champaign astronomy and physics professor Brian Fields explores the possibility that astronomical events were responsible for an extinction event 359 million years ago, at the boundary between the Devonian and Carboniferous periods.The paper is published in the The team concentrated on the Devonian-Carboniferous boundary because those rocks contain hundreds of thousands of generations of plant spores that appear to be sunburnt by ultraviolet light -- evidence of a long-lasting ozone-depletion event."Earth-based catastrophes such as large-scale volcanism and global warming can destroy the ozone layer, too, but evidence for those is inconclusive for the time interval in question," Fields said. "Instead, we propose that one or more supernova explosions, about 65 light-years away from Earth, could have been responsible for the protracted loss of ozone.""To put this into perspective, one of the closest supernova threats today is from the star Betelgeuse, which is over 600 light-years away and well outside of the kill distance of 25 light-years," said graduate student and study co-author Adrienne Ertel.The team explored other astrophysical causes for ozone depletion, such as meteorite impacts, solar eruptions and gamma-ray bursts. "But these events end quickly and are unlikely to cause the long-lasting ozone depletion that happened at the end of the Devonian period," said graduate student and study co-author Jesse Miller.A supernova, on the other hand, delivers a one-two punch, the researchers said. The explosion immediately bathes Earth with damaging UV, X-rays and gamma rays. Later, the blast of supernova debris slams into the solar system, subjecting the planet to long-lived irradiation from cosmic rays accelerated by the supernova. The damage to Earth and its ozone layer can last for up to 100,000 years.However, fossil evidence indicates a 300,000-year decline in biodiversity leading up to the Devonian-Carboniferous mass extinction, suggesting the possibility of multiple catastrophes, maybe even multiple supernovae explosions. "This is entirely possible," Miller said. "Massive stars usually occur in clusters with other massive stars, and other supernovae are likely to occur soon after the first explosion."The team said the key to proving that a supernova occurred would be to find the radioactive isotopes plutonium-244 and samarium-146 in the rocks and fossils deposited at the time of extinction. "Neither of these isotopes occurs naturally on Earth today, and the only way they can get here is via cosmic explosions," said undergraduate student and co-author Zhenghai Liu.The radioactive species born in the supernova are like green bananas, Fields said. "When you see green bananas in Illinois, you know they are fresh, and you know they did not grow here. Like bananas, Pu-244 and Sm-146 decay over time. So if we find these radioisotopes on Earth today, we know they are fresh and not from here -- the green bananas of the isotope world -- and thus the smoking guns of a nearby supernova."Researchers have yet to search for Pu-244 or Sm-146 in rocks from the Devonian-Carboniferous boundary. Fields' team said its study aims to define the patterns of evidence in the geological record that would point to supernova explosions."The overarching message of our study is that life on Earth does not exist in isolation," Fields said. "We are citizens of a larger cosmos, and the cosmos intervenes in our lives -- often imperceptibly, but sometimes ferociously."Also participating in the study were scientists from the University of Kansas; Kings College, UK; the European Organization for Nuclear Research, Switzerland; the National Institute of Chemical Physics and Biophysics, Estonia; the United States Air Force Academy; and Washburn University.The Science and Technology Facilities Council and the Estonian Research Council supported this study. | Ozone Holes | 2,020 |
July 28, 2020 | https://www.sciencedaily.com/releases/2020/07/200727194737.htm | Lockdown saw modest drop in China air pollution, study finds | Large improvements of air quality in China during the COVID-19 lockdown have been widely reported, but new research reveals that the two pollutants most harmful to human health, fine particulate matter (PM2.5) and ozone, were only slightly reduced. | The study, by scientists from the University of Leeds, UK and the Southern University of Science and Technology, China, analysed air pollutant concentrations from China's national network of around 1,300 monitoring stations to quantify the response of air pollution across China during the COVID-19 lockdown.They found that the falls in some air pollutants like nitrogen dioxide (NOThe study is published today in the IOP Publishing journalSenior author Professor Dominick Spracklen, from the University of Leeds, said: "Although China's air quality has improved in recent years, indoor and outdoor air pollution still has serious health impacts, with 12 per cent of deaths in China in 2017 attributable to it."Understanding trends in air quality is therefore essential to assess the effectiveness of recent air quality measures and help inform future air pollution mitigation. The application of control measures during the COVID-19 outbreak enabled us to analyse the potential air quality improvements resulting from a reduction in emissions."To understand the impact of the control measures during the COVID-19 outbreak, the researchers compared pollutant concentrations in 2020 with expected concentrations had the COVID-19 outbreak not occurred.They used a time series of China-wide measurements of key pollutant concentrations, from January 2015 to April 2020, to isolate the changes during the lockdown period compared with concentrations otherwise expected based on recent trends, seasonality, and the effects of the Lunar New Year (the precise date of which changes from year to year).Lead author Ben Silver, from the University of Leeds, said: "During the lockdown period in China, defined as January 23rd to March 31st, 2020, we found that the largest reductions occurred in NO"Much smaller reductions were observed for other pollutants. PMCo-author Xinyue He, from the Southern University of Science and Technology, Shenzen, China, said: "Chinese NO"PMProfessor Spracklen added: "The modest improvement in air quality during the lockdown, despite very large reductions in emissions from some sources such as traffic, highlights the challenge facing China as it tries to further improve air quality."Our study provides insight into the effects of future emission reductions and can help inform development of effective air pollution mitigation strategies." | Ozone Holes | 2,020 |
July 20, 2020 | https://www.sciencedaily.com/releases/2020/07/200720093238.htm | Geoengineering is just a partial solution to fight climate change | Could we create massive sulfuric acid clouds that limit global warming and help meet the 2015 Paris international climate goals, while reducing unintended impacts? | Yes, in theory, according to a Rutgers co-authored study in the journal But the regional impacts of geoengineering, including on precipitation and the Antarctic ozone layer hole, depend on how much greenhouse gas emissions from humanity are being reduced simultaneously. If carbon dioxide emissions from burning coal, oil and natural gas continue unabated, geoengineering would not prevent large decreases in precipitation and depletion of the life-sustaining ozone layer. If society launches massive efforts to reduce carbon emissions, remove carbon dioxide from the atmosphere and adapt to climate change, small doses of geoengineering may help reduce the most dangerous aspects of global warming, the study says."Our research shows that no single technology to combat climate change will fully address the growing crisis, and we need to stop burning fossil fuels and aggressively harness wind and solar energy to power society ASAP," said co-author Alan Robock, a Distinguished Professor in the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "This mitigation is needed whether society ever decides to deploy geoengineering or not."Using a climate model, scientists studied whether it's possible to create sulfuric acid clouds in the stratosphere to reflect solar radiation and limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) or 2 degrees Celsius (3.6 degrees Fahrenheit) above preindustrial temperatures. Those two goals were set at the 2015 United Nations climate change conference in Paris to try to reduce the negative impacts of global warming.Robock noted that the study was done with only one climate model that addressed different global warming and geoengineering scenarios. Other studies are needed to check the robustness of the results and to further examine the potential risks of any geoengineering scheme.Lili Xia, a Rutgers research scientist, co-authored study. Scientists at the National Center for Atmospheric Research, Cornell University, University of Colorado, Boulder, Utrecht University, Delft University of Technology, University of Texas, Rio Grande Valley, Indiana University and Pacific Northwest National Laboratory contributed. | Ozone Holes | 2,020 |
June 30, 2020 | https://www.sciencedaily.com/releases/2020/06/200630155750.htm | Removing toxic chemicals from water: New environmentally-friendly method | Researchers from Swansea University have developed a new environmentally friendly method for removing toxic chemicals from water. | A newly invented machine, called the Matrix Assembly Cluster Source (MACS), has been used to design a breakthrough water treatment method using a solvent-free approach.The research, from The Institute for Innovative Materials, Processing and Numerical Technologies (IMPACT) within the College of Engineering at Swansea University, was funded by the EPSRC and led by Professor Richard Palmer.Professor Richard Palmer explains: "The harmful organic molecules are destroyed by a powerful oxidising agent, ozone, which is boosted by a catalyst. Usually such catalysts are manufactured by chemical methods using solvents, which creates another problem -- how to deal with the effluents from the manufacturing process?The Swansea innovation is a newly invented machine that manufactures the catalyst by physical methods, involving no solvent, and therefore no effluent. The new technique is a step change in the approach to water treatment and other catalytic processes."Professor Palmer continues: "Our new approach to making catalysts for water treatments uses a physical process which is vacuum-based and solvent free method. The catalyst particles are clusters of silver atoms, made with the newly invented MACS machine.It solves the long-standing problem of low cluster production rate -- meaning, for the first time, it is now possible to produce enough clusters for study at the test-tube level, with the potential to then scale-up further to the level of small batch manufacturing and beyond."The clusters are approximately 10,000 times smaller than the width of a human hair and have been of significant interest to researchers because of their unique properties. However, due to the inadequate rate of cluster production, research in this area has been limited.The new MACS method has changed this -- it scales up the intensity of the cluster beam to produce enough grams of cluster powder for practical testing. The addition of ozone to the powder then destroys pollutant chemicals from water, in this case nitrophenol.On the future potential of this breakthrough technology, Professor Palmer summarises: "The MACS approach to the nanoscale design of functional materials opens up completely new horizons across a wide range of disciplines -- from physics and chemistry to biology and engineering. Thus, it has the power to enable radical advances in advanced technology -- catalysts, biosensors, materials for renewable energy generation and storage.It seems highly appropriate that the first practical demonstration of Swansea's environmentally friendly manufacturing process concerns something we are all concerned about -- clean water!" | Ozone Holes | 2,020 |
May 27, 2020 | https://www.sciencedaily.com/releases/2020/05/200527150158.htm | Erosion of ozone layer responsible for mass extinction event | Researchers at the University of Southampton have shown that an extinction event 360 million years ago, that killed much of the Earth's plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer that shields the Earth from damaging ultraviolet (UV) radiation. This is a newly discovered extinction mechanism with profound implications for our warming world today. | There have been a number of mass extinction in the geological past. Only one was caused by an asteroid hitting the Earth, which was 66 million years ago when the dinosaurs became extinct. Three of the others, including the end Permian Great Dying, 252 million years ago, were caused by huge continental scale volcanic eruptions that destabilised the Earth's atmospheres and oceans.Now, scientists have found evidence showing it was high levels of UV radiation which collapsed forest ecosystems and killed off many species of fish and tetrapods (our four limbed ancestors) at the end of the Devonian geological period, 359 million years ago. This damaging burst of UV radiation occurred as part of one of the Earth's climate cycles, rather than being caused by a huge volcanic eruption.The ozone collapse occurred as the climate rapidly warmed following an intense ice age and the researchers suggest that the Earth today could reach comparable temperatures, possibly triggering a similar event. Their findings are published in the journal The team collected rock samples during expeditions to mountainous polar-regions in East Greenland, which once formed a huge ancient lake bed in the arid interior of the Old Red Sandstone Continent, made up of Europe and North America. This lake was situated in the Earth's southern hemisphere and would have been similar in nature to modern day Lake Chad on the edge of the Sahara Desert.Other rocks were collected from the Andean Mountains above Lake Titicaca in Bolivia. These South American samples were from the southern continent of Gondwana, which was closer to the Devonian South Pole. They held clues as to what was happening at the edge of the melting Devonian ice sheet, allowing a comparison between the extinction event close to the pole and close to the equator.Back in the lab, the rocks were dissolved in hydrofluoric acid, releasing microscopic plant spores (like pollen, but from fern like plants that didn't have seeds or flowers) which had lain preserved for hundreds of millions of years. On microscopic examination, the scientists found many of the spores had bizarrely formed spines on their surface -- a response to UV radiation damaging their DNA. Also, many spores had dark pigmented walls, thought to be a kind of protective 'tan', due to increased and damaging UV levels.The scientists concluded that, during a time of rapid global warming, the ozone layer collapsed for a short period, exposing life on Earth to harmful levels of UV radiation and triggering a mass extinction event on land and in shallow water at the Devonian-Carboniferous boundary.Following melting of the ice sheets, the climate was very warm, with the increased heat above continents pushing more naturally generated ozone destroying chemicals into the upper atmosphere. This let in high levels of UV-B radiation for several thousand years.Lead researcher Professor John Marshall, of the University of Southampton's School of Ocean and Earth Science, who is a National Geographic Explorer, comments: "Our ozone shield vanished for a short time in this ancient period, coinciding with a brief and quick warming of the Earth. Our ozone layer is naturally in a state of flux -- constantly being created and lost -- and we have shown this happened in the past too, without a catalyst such as a continental scale volcanic eruption."During the extinction, plants selectively survived, but were enormously disrupted as the forest ecosystem collapsed. The dominant group of armoured fish became extinct. Those that survived -- sharks and bony fish -- remain to this day the dominant fish in our ecosystems.These extinctions came at a key time for the evolution of our own ancestors, the tetrapods. These early tetrapods are fish that evolved to have limbs rather than fins, but still mostly lived in water. Their limbs possessed many fingers and toes. The extinction reset the direction of their evolution with the post-extinction survivors being terrestrial and with the number of fingers and toes reduced to five.Professor Marshall says his team's findings have startling implications for life on Earth today: "Current estimates suggest we will reach similar global temperatures to those of 360 million years ago, with the possibility that a similar collapse of the ozone layer could occur again, exposing surface and shallow sea life to deadly radiation. This would move us from the current state of climate change, to a climate emergency."The remote locations visited in East Greenland are very difficult to access, with travel involving light aircraft capable of landing directly on the tundra. Transport within the vast field area was by inflatable boats equipped with outboard motors, all of which had to fit in the small aircraft.All field logistics was organised by CASP, an independent charitable trust based in Cambridge specialising in remote geological fieldwork. Mike Curtis, Managing Director of CASP says: "We have a history of assisting research geologists such as John Marshall and colleagues to access remote field areas and we are particularly pleased that their research has proved to have such potentially profound implications." | Ozone Holes | 2,020 |
May 14, 2020 | https://www.sciencedaily.com/releases/2020/05/200514131712.htm | CFC replacements are a source of persistent organic pollution in the Arctic | Substances used to replace ozone-depleting chlorofluorocarbons (CFCs) may be just as problematic as their predecessors, a new study shows. | In 1987, Canada implemented the Montreal Protocol, a global agreement to protect Earth's ozone layer by ceasing the use of substances like CFCs. Unfortunately, the CFC-replacement substances used to replace them are proving problematic as well, with accumulating levels of their degradation products recently found in the Canadian Arctic."In many ways, the degradation products from these substances may be just as concerning as the original chemical they were meant to replace," said Alison Criscitiello, director of the Canadian Ice Core Lab (CICL), housed in the University of Alberta's Faculty of Science. "We are seeing significant levels of these short-chain acids accumulating in the Devon Ice Cap, and this study links some of them directly to CFC replacement compounds."An ice core drilled on the summit of Devon Ice Cap in the Canadian high Arctic shows a tenfold increase in short-chain perfluorocarboxylic acid (scPFCA) deposition between 1986 and 2014. scPFCAs form through atmospheric oxidation of several industrial chemicals, some of which are CFC replacement compounds. scPFCAs are highly mobile persistent organic pollutants and belong to the class of so-called "forever chemicals" because they do not break down. A few preliminary studies have shown toxicity of these substances to plants and invertebrates."This is the first multi-decadal temporal record of scPFCA deposition in the Arctic," explained Criscitiello. "Our results suggest that the CFC-replacement compounds mandated by the Montreal Protocol are the dominant source of some scPFCAs to remote regions."Over the past four years, Criscitiello and colleagues drilled four ice cores across the eastern Canadian high Arctic. This interdisciplinary work is thanks to a strong collaboration between Criscitiello and the labs of York University atmospheric chemist Cora Young and Environment and Climate Change Canada research scientist Amila De Silva.These same Canadian Arctic ice cores also contain significant levels of perfluoroalkyl acids (PFAAs). These results demonstrate that both perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS) have continuous and increasing deposition on the Devon Ice Cap despite North American and international regulations and phase-outs. This is the likely result of ongoing manufacture, use, and emissions of these persistent pollutants, as well as their precursors and other new compounds in regions outside of North America."These results show the need for a more holistic approach when deciding to ban and replace chemical compounds," explained Criscitiello. "Chemicals degrade, and developing a strong understanding of how they degrade in the environment, and what they degrade to, is vital." | Ozone Holes | 2,020 |
May 11, 2020 | https://www.sciencedaily.com/releases/2020/05/200511124444.htm | COVID-19 lockdowns significantly impacting global air quality | Levels of two major air pollutants have been drastically reduced since lockdowns began in response to the COVID-19 pandemic, but a secondary pollutant -- ground-level ozone -- has increased in China, according to new research. | Two new studies in AGU's journal In addition to nitrogen dioxide, one of the new studies finds particulate matter pollution (particles smaller than 2.5 microns) has decreased by 35 percent in northern China. Particulate matter is composed of solid particles and liquid droplets that are small enough to penetrate deep into the lungs and cause damage.The two new papers are part of an ongoing special collection of research in AGU journals related to the current pandemic.Such a significant drop in emissions is unprecedented since air quality monitoring from satellites began in the 1990s, said Jenny Stavrakou, an atmospheric scientist at the Royal Belgian Institute for Space Aeronomy in Brussels and co-author of one of the papers. The only other comparable events are short-term reductions in China's emissions due to strict regulations during events like the 2008 Beijing Olympics.The improvements in air quality will likely be temporary, but the findings give scientists a glimpse into what air quality could be like in the future as emissions regulations become more stringent, according to the researchers."Maybe this unintended experiment could be used to understand better the emission regulations," Stavrakou said. "It is some positive news among a very tragic situation."However, the drop in nitrogen dioxide pollution has caused an increase in surface ozone levels in China, according to one of the new studies. Ozone is a secondary pollutant formed when sunlight and high temperature catalyze chemical reactions in the lower atmosphere. Ozone is harmful to humans at ground-level, causing pulmonary and heart disease.In highly polluted areas, particularly in winter, surface ozone can be destroyed by nitrogen oxides, so ozone levels can increase when nitrogen dioxide pollution goes down. As a result, although air quality has largely improved in many regions, surface ozone can still be a problem, according to Guy Brasseur, an atmospheric scientist at the Max Planck Institute for Meteorology in Hamburg, Germany, and lead author of one of the new studies."It means that by just reducing the [nitrogen dioxide] and the particles, you won't solve the ozone problem," Brasseur said.Stavrakou and her colleagues used satellite measurements of air quality to estimate the changes in nitrogen dioxide pollution over the major epicenters of the outbreak: China, South Korea, Italy, Spain, France, Germany, Iran and the United States.They found that nitrogen dioxide pollution decreased by an average of 40 percent over Chinese cities and by 20 to 38 percent over Western Europe and the United States during the 2020 lockdown, as compared to the same time in 2019.However, the study found nitrogen dioxide pollution did not decrease over Iran, one of the earliest and hardest-hit countries. The authors suspect this is because complete lockdowns weren't in place until late March and before that, stay-at-home orders were largely ignored. The authors did see a dip in emissions during the Iranian New Year holiday after March 20, but this dip is observed during the celebration every year.The second study looked at air quality changes in northern China where the virus was first reported and where lockdowns have been most strict.Brasseur analyzed levels of nitrogen dioxide and several other types of air pollution measured by 800 ground-level air quality monitoring stations in northern China.Brasseur and his colleague found particulate matter pollution decreased by an average of 35 percent and nitrogen dioxide decreased by an average of 60 percent after the lockdowns began on January 23.However, they found the average surface ozone concentration increased by a factor of 1.5-2 over the same time period. At ground level, ozone forms from complex reactions involving nitrogen dioxide and volatile organic compounds (VOCs), gases emitted by a variety of household and industrial products, but ozone levels can also be affected by weather conditions and other factors. | Ozone Holes | 2,020 |
April 21, 2020 | https://www.sciencedaily.com/releases/2020/04/200421090554.htm | Nearly half of US breathing unhealthy air; record-breaking air pollution in nine cities | This year marks the 50th anniversary of the Clean Air Act, which is responsible for dramatic improvements in air quality. Despite this, a new report from the American Lung Association finds nearly half of the nation's population -- 150 million people -- lived with and breathed polluted air, placing their health and lives at risk. The 21st annual "State of the Air" report finds that climate change continues to make air pollution worse, with many western communities again experiencing record-breaking spikes in particle pollution due to wildfires. Amid the COVID-19 pandemic, the impact of air pollution on lung health is of heightened concern. | The 2020 "State of the Air" report analyzed data from 2016, 2017 and 2018, the three years with the most recent quality-assured air pollution data. Notably, those three years were among the five hottest recorded in global history. When it comes to air quality, changing climate patterns fuel wildfires and their dangerous smoke, and lead to worsened particle and ozone pollution. This degraded air quality threatens everyone, especially children, older adults and people living with a lung disease."The report finds the air quality in some communities has improved, but the 'State of the Air' finds that far too many people are still breathing unhealthy air," said American Lung Association President and CEO Harold Wimmer. "This year's report shows that climate change continues to degrade air quality and increase the risk of air pollution harming health. To protect the advances in air quality we fought for 50 years ago through the Clean Air Act, we must again act today, implementing effective policies to protect our air quality and lung health against the threat of climate change.""Air pollution is linked to greater risk of lung infection," Wimmer added. "Protecting everyone from COVID-19 and other lung infections is an urgent reminder of the importance of clean air."Each year, "State of the Air" reports on the two most widespread outdoor air pollutants, ozone pollution and particle pollution. Each is dangerous to public health and can be lethal. The 2020 "State of the Air" report found that more than 20.8 million people lived in counties that had unhealthy levels of air pollution in all categories from 2016 to 2018. Below are the report findings for each category graded.Unhealthy particles in the air come from wildfires, wood-burning stoves, coal-fired power plants, diesel engines and other sources. Particle pollution can be deadly. Technically known as PM2.5, these microscopic particles lodge deep in the lungs and can even enter the bloodstream. Particle pollution can trigger asthma attacks, heart attacks and strokes and cause lung cancer. New research also links air pollution to the development of serious diseases, such as asthma and dementia.The report has two grades for particle pollution: one for "short-term" particle pollution, or daily spikes, and one for the annual average, "year-round" level that represents the concentration of particles day-in and day-out in each location.More cities experienced more days with spikes in particle pollution in this year's report. In fact, nine western cities reached their most days ever reported. These deadly spikes were driven in large part by smoke from major wildfires in 2018, especially in California, and some locations also saw spikes from woodsmoke from heating homes. Of note, 24 of the 25 most polluted cities were located in the western region of the U.S. Nationwide, more than 53.3 million people experienced these unhealthy spikes in particle pollution.Top 10 U.S. Cities Most Polluted by Short-term Particle Pollution (24-hour PM2.5):2. Bakersfield, California3. San Jose-San Francisco-Oakland, California4. Fairbanks, Alaska5. Yakima, Washington6. Los Angeles-Long Beach, California7. Missoula, Montana8. Redding-Red Bluff, California9. Salt Lake City-Provo-Orem, Utah10. Phoenix-Mesa, ArizonaMore than 21.2 million people lived in counties with unhealthy levels of year-round particle pollution, which is more than in the last three "State of the Air" reports. Progress toward healthy air continued in many places thanks to steps taken to clean up emissions that lead to particle pollution, but 13 of the 26 most polluted cities faced worse levels of year-round particle pollution. Some cities had so many days of short-term particle pollution spikes that the sheer number led to them having higher annual averages as well.Many cities experienced their cleanest ever annual average, yet remained on the nation's most polluted list. Despite making the top 10 most polluted list, both Fresno-Madera-Hanford, California and Pittsburgh metro area tied with their previous record of cleanest air in the 21-year history of the report. And while Chicago, Cincinnati and Indianapolis made the top 25 most polluted list, each hit their cleanest ever annual average.Top 10 U.S. Cities Most Polluted by Year-Round Particle Pollution (Annual PM2.5):2. Fresno-Madera-Hanford, California3. Visalia, California4. Los Angeles-Long Beach, California5. San Jose-San Francisco-Oakland, California6. Fairbanks, Alaska7. Phoenix-Mesa, Arizona8. El Centro, California8. Pittsburgh-New Castle-Weirton, PA-OH-WV10. Detroit-Warren-Ann Arbor, MichiganOzone pollution, often referred to as smog, is a powerful respiratory irritant whose effects have been likened to a sunburn of the lung. Inhaling ozone can cause shortness of breath, trigger coughing and asthma attacks and may shorten life. Warmer temperatures driven by climate change make ozone more likely to form and harder to clean up.Significantly more people suffered unhealthy ozone pollution in the 2020 report than in the last three "State of the Air" reports. More than 137 million people lived in area county earning a failing grade for ozone pollution. This shows the changing climate's impact on air quality, as ozone pollution worsened during the global record-breaking heat years tracked in the 2020 report. However, despite making the top ten list of most ozone-polluted cities, San Jose-San Francisco-Oakland, California experienced its best-ever air quality for ozone.Top 10 Most Ozone-Polluted Cities:2. Visalia, California3. Bakersfield, California4. Fresno-Madera-Hanford, California5. Sacramento-Roseville, California6. San Diego-Chula Vista-Carlsbad, California7. Phoenix-Mesa, Arizona8. San Jose-San Francisco-Oakland, California9. Las Vegas-Henderson, Nevada10. Denver-Aurora, ColoradoThe "State of the Air" also recognizes the nation's four cleanest cities. To make the list, a city must experience no high ozone or high particle pollution days and must rank among the 25 cities with the lowest year-round particle pollution levels.Cleanest U.S. Cities (listed in alphabetical order)"The science is clear: the nation needs stronger limits on ozone and particle pollution to safeguard health, especially for children and people with lung disease," Wimmer said. "Every family has the right to breathe healthy air -- and the right to know when air pollution levels are unhealthy. The Clean Air Act is a powerful protector of public health and Americans breathe healthier air today because of this landmark law. But climate change poses increasingly dire threats to air quality and lung health, and our leaders must take immediate, significant action to safeguard the air we all breathe." | Ozone Holes | 2,020 |
April 16, 2020 | https://www.sciencedaily.com/releases/2020/04/200416135944.htm | Arctic stratospheric ozone levels hit record low in March | Ozone levels above the Arctic reached a record low for March, NASA researchers report. An analysis of satellite observations show that ozone levels reached their lowest point on March 12 at 205 Dobson units. | While such low levels are rare, they are not unprecedented. Similar low ozone levels occurred in the upper atmosphere, or stratosphere, in 1997 and 2011. In comparison, the lowest March ozone value observed in the Arctic is usually around 240 Dobson units."This year's low Arctic ozone happens about once per decade," said Paul Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "For the overall health of the ozone layer, this is concerning since Arctic ozone levels are typically high during March and April."Ozone is a highly reactive molecule comprised of three oxygen atoms that occurs naturally in small amounts. The stratospheric ozone layer, roughly 7 to 25 miles above Earth's surface, is a sunscreen, absorbing harmful ultraviolet radiation that can damage plants and animals and affecting people by causing cataracts, skin cancer and suppressed immune systems.The March Arctic ozone depletion was caused by a combination of factors that arose due to unusually weak upper atmospheric "wave" events from December through March. These waves drive movements of air through the upper atmosphere akin to weather systems that we experience in the lower atmosphere, but much bigger in scale.In a typical year, these waves travel upward from the mid-latitude lower atmosphere to disrupt the circumpolar winds that swirl around the Arctic. When they disrupt the polar winds, they do two things. First, they bring with them ozone from other parts of the stratosphere, replenishing the reservoir over the Arctic."Think of it like having a red-paint dollop, low ozone over the North Pole, in a white bucket of paint," Newman said. "The waves stir the white paint, higher amounts of ozone in the mid-latitudes, with the red paint or low ozone contained by the strong jet stream circling around the pole."The mixing has a second effect, which is to warm the Arctic air. The warmer temperatures then make conditions unfavorable for the formation of polar stratospheric clouds. These clouds enable the release of chlorine for ozone-depleting reactions. Ozone depleting chlorine and bromine come from chlorofluorocarbons and halons, the chemically active forms of chlorine and bromine derived from human-made compounds that are now banned by the Montreal Protocol. The mixing shuts down this chlorine and bromine driven ozone depletion.In December 2019 and January through March of 2020, the stratospheric wave events were weak and did not disrupt the polar winds. The winds thus acted like a barrier, preventing ozone from other parts of the atmosphere from replenishing the low ozone levels over the Arctic. In addition, the stratosphere remained cold, leading to the formation of polar stratospheric clouds which allowed chemical reactions to release reactive forms of chlorine and cause ozone depletion."We don't know what caused the wave dynamics to be weak this year," Newman said. "But we do know that if we hadn't stopped putting chlorofluorocarbons into the atmosphere because of the Montreal Protocol, the Arctic depletion this year would have been much worse."Since 2000, levels of chlorofluorocarbons and other human-made ozone-depleting substances have measurably decreased in the atmosphere and continue to do so. Chlorofluorocarbons are long-lived compounds that take decades to break down, and scientists expect stratospheric ozone levels to recover to 1980 levels by mid-century.NASA researchers prefer the term "depletion" over the Arctic, since despite the ozone layer's record low this year, the ozone loss is still much less than the annual ozone "hole" that occurs over Antarctica in September and October during Southern Hemisphere spring. For comparison, ozone levels over Antarctica typically drop to about 120 Dobson units.NASA, along with the National Oceanic and Atmospheric Administration, monitors stratospheric ozone using satellites, including NASA's Aura satellite, the NASA-NOAA Suomi National Polar-orbiting Partnership satellite and NOAA's Joint Polar Satellite System NOAA-20. The Microwave Limb Sounder aboard the Aura satellite also estimates stratospheric levels of ozone-destroying chlorine. | Ozone Holes | 2,020 |
March 25, 2020 | https://www.sciencedaily.com/releases/2020/03/200325120840.htm | International ozone treaty stops changes in Southern Hemisphere winds | Chemicals that deplete Earth's protective ozone layer have also been triggering changes in Southern Hemisphere atmospheric circulation. Now, new research in | "This study adds to growing evidence showing the profound effectiveness of the Montreal Protocol. Not only has the treaty spurred healing of the ozone layer, it's also driving recent changes in Southern Hemisphere air circulation patterns," said lead author Antara Banerjee, a CIRES Visiting Fellow at the University of Colorado Boulder who works in the Chemical Sciences Division of the National Oceanic and Atmospheric Administration (NOAA). She started this work as a Postdoctoral Fellow at Columbia University.The ozone hole, discovered in 1985, has been forming every spring in the atmosphere high over Antarctica. Ozone depletion cools the air, strengthening the winds of the polar vortex and affecting winds all the way down to the lowest layer of Earth's atmosphere. Ultimately, ozone depletion has shifted the midlatitude jet stream and the dry regions at the edge of the tropics toward the South Pole.Previous studies have linked these circulation trends to weather changes in the Southern Hemisphere, especially rainfall over South America, East Africa, and Australia, and to changes in ocean currents and salinity.The Montreal Protocol of 1987 phased out production of ozone-destroying substances such as chlorofluorocarbons (CFCs). Beginning around 2000, concentrations of those chemicals in the stratosphere started to decline and the ozone hole began to recover. In this study, Banerjee and her co-authors have shown that around the year 2000, the circulation of the Southern Hemisphere also stopped expanding polewards -- a pause or slight reversal of the earlier trends."The challenge in this study was proving our hypothesis that ozone recovery is in fact driving these atmospheric circulation changes and it isn't just a coincidence," Banerjee said.To do that, the researchers used a two-step statistical technique called detection and attribution: detecting whether certain patterns of observed wind changes are unlikely to be due to natural variability alone and, if so, whether the changes can be attributed to human-caused factors, such as emissions of ozone-depleting chemicals and COUsing computer simulations, the researchers first determined that the observed pause in circulation trends couldn't be explained by natural shifts in winds alone. Next, they isolated the effects of ozone and greenhouse gases separately.They showed that while rising CO"Identifying the ozone-driven pause in circulation trends in real-world observations confirms, for the first time, what the scientific ozone community has long predicted from theory," said John Fyfe, a scientist at Environment and Climate Change Canada and one of the paper's co-authors.With ozone beginning to recover and CO"We term this a 'pause' because the poleward circulation trends might resume, stay flat, or reverse," Banerjee said. "It's the tug of war between the opposing effects of ozone recovery and rising greenhouse gases that will determine future trends." | Ozone Holes | 2,020 |
March 17, 2020 | https://www.sciencedaily.com/releases/2020/03/200317130722.htm | Emissions of several ozone-depleting chemicals are larger than expected | In 2016, scientists at MIT and elsewhere observed the first signs of healing in the Antarctic ozone layer. This environmental milestone was the result of decades of concerted effort by nearly every country in the world, which collectively signed on to the Montreal Protocol. These countries pledged to protect the ozone layer by phasing out production of ozone-depleting chlorofluorocarbons, which are also potent greenhouse gases. | While the ozone layer is on a recovery path, scientists have found unexpectedly high emissions of CFC-11 and CFC-12, raising the possibility of production of the banned chemicals that could be in violation of the landmark global treaty. Emissions of CFC-11 even showed an uptick around 2013, which has been traced mainly to a source in eastern China. New data suggest that China has now tamped down on illegal production of the chemical, but emissions of CFC-11 and 12 emission are still larger than expected.Now MIT researchers have found that much of the current emission of these gases likely stems from large CFC "banks" -- old equipment such as building insulation foam, refrigerators and cooling systems, and foam insulation, that was manufactured before the global phaseout of CFCs and is still leaking the gases into the atmosphere. Based on earlier analyses, scientists concluded that CFC banks would be too small to contribute very much to ozone depletion, and so policymakers allowed the banks to remain.It turns out there are oversized banks of both CFC-11 and CFC-12. The banks slowly leak these chemicals at concentrations that, if left unchecked, would delay the recovery of the ozone hole by six years and add the equivalent of 9 billion metric tons of carbon dioxide to the atmosphere -- an amount that is similar to the current European Union pledge under the UN Paris Agreement to reduce climate change."Wherever these CFC banks reside, we should consider recovering and destroying them as responsibly as we can," says Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies at MIT, who is a co-author of the study. "Some banks are easier to destroy than others. For instance, before you tear a building down, you can take careful measures to recover the insulation foam and bury it in a landfill, helping the ozone layer recover faster and perhaps taking off a chunk of global warming as a gift to the planet."The team also identified an unexpected and sizable source of another ozone-depleting chemical, CFC-113. This chemical was traditionally used as a cleaning solvent, and its production was banned, except for in one particular use, as a feedstock for the manufacturing of other chemical substances. It was thought that chemical plants would use the CFC-113 without allowing much leakage, and so the chemical's use as a feedstock was allowed to continue.However, the researchers found that CFC-113 is being emitted into the atmosphere, at a rate of 7 billion grams per year -- nearly as large as the spike in CFC-11, which amounted to about 10 billion grams per year."A few years ago, the world got very upset over 10 gigagrams of CFC-11 that wasn't supposed to be there, and now we're seeing 7 gigagrams of CFC-113 that wasn't supposed to be there," says lead author of the study and MIT graduate student Megan Lickley. "The two gases are similar in terms of their ozone depletion and global warming potential. So this is a significant issue."The study appears in The new results are based on an analysis the team developed that combines two common methods for estimating the size of CFC banks around the world.The first method is a top-down approach, which looks at CFCs produced around the world, based on country-by-country reporting, and then compares these numbers to actual concentrations of the gasses and how long they persist in the atmosphere. After accounting for atmospheric destruction, the difference between a chemical's production and its atmospheric concentrations gives scientists an estimate of the size of CFC banks around the world.Based on recent international assessments that use this top-down approach, there should be no CFC banks left in the world."But those values are subject to large uncertainties: Small differences in production values or lifetimes or concentrations can lead to large differences in the bank size," Lickley notes.The second method is a bottom-up approach, which uses industry-reported values of CFC production and sales in a variety of applications such as refrigeration or foams, and estimates of how quickly each equipment type is depleting over time.The team combined the best of both methods in a Bayesian probabilistic model -- a hybrid approach that calculates the global size of CFC banks based on both atmospheric data, and country and industry-level reporting of CFC production and sales in various uses."We also allow there to be some uncertainties, because there could be reporting errors from different countries, which wouldn't be surprising at all," Solomon says. "So it's a much better quantification of the size of the bank."The CFC banks, and the sheer quantity of old equipment storing these chemicals around the world, seem to be larger than any previous estimates. The team found the amount of CFC 11 and 12 stored up in banks is about 2.1 million metric tons -- an amount that would delay ozone recovery by six years if released to the atmosphere. This CFC bank is also equivalent to about 9 billion metric tons of carbon dioxide in terms of its effect on climate change.Interestingly, the amount of both CFC-11 and CFC-12 that is being emitted from these banks is enough to account for the recently observed emissions in both gases."It really looks like, other than the extra amount being produced in China that seems to have stopped now, the rest of what we're seeing is no mystery: It's just what's coming out of the banks. That's good news," Solomon says. "It means there doesn't seem to be any further cheating going on. If there is, it's very small. And we wanted to know, if you were to recover and destroy these building foams, and replace old cooling systems and such, in a more responsible way, what more could that do for climate change?"To answer that, the team explored several theoretical policy scenarios and their potential effect on the emissions produced by CFC banks.An "opportunity lost" scenario considers what would have happened if all banks were destroyed back in 2000 -- the year that many developed countries agreed to phase out CFC production. If this scenario had played out, the measure would have saved the equivalent of 25 billion metric tons of carbon dioxide between 2000 and 2020, and there would be no CFC emissions lingering now from these banks.A second scenario predicts CFC emissions in the atmosphere if all banks are recovered and destroyed in 2020. This scenario would save the equivalent of 9 billion metric tons of carbon dioxide emitted to the atmosphere. If these banks were destroyed today, it would also help the ozone layer recover six years faster."We lost an opportunity in 2000, which is really sad," Solomon says. "So let's not miss it again."This research was supported, in part, by VoLo foundation. Solomon is also supported by a Lee and Geraldine Martin Professorship. | Ozone Holes | 2,020 |
March 12, 2020 | https://www.sciencedaily.com/releases/2020/03/200312101033.htm | Can poor air quality make you gain weight? | Breathing dirty air takes a heavy toll on gut bacteria, boosting risk of obesity, diabetes, gastrointestinal disorders and other chronic illnesses, new University of Colorado Boulder research suggests. | The study, published online in the journal The gaseous pollutant ozone, which helps make up Denver's infamous 'brown cloud' -- is particularly hazardous, the study found, with young adults exposed to higher levels of ozone showing less microbial diversity and more of certain species associated with obesity and disease."We know from previous research that air pollutants can have a whole host of adverse health effects," said senior author Tanya Alderete, an assistant professor of integrative physiology, pointing to studies linking smog with Type 2 diabetes, weight gain and inflammatory bowel diseases. "The takeaway from this paper is that some of those effects might be due to changes in the gut."The study comes at a time when air quality in many U.S. cities is worsening after decades of improvement. In December, the Environmental Protection Agency downgraded the Denver metro and north Front Range regions to "serious non-attainment" status for failing to meet national ozone standards.Regions of eight other states, including some in California, Texas, Illinois, Connecticut, Indiana, New Jersey, New York and Wisconsin, were also penalized for high ozone. Worldwide, according to research published this month, air pollution kills 8.8 million people annually -- more than smoking or war.While much attention has been paid to respiratory health, Alderete's previous studies have shown pollution can also impair the body's ability to regulate blood sugar and influence risk for obesity. Other research has shown visits to emergency rooms for gastrointestinal problems spike on high pollution days, and youth with high exposure to traffic exhaust have greater risk of developing Crohn's disease.To investigate just what might be going on inside the gut, Alderete's team used cutting-edge whole-genome sequencing to analyze fecal samples from 101 young adults in Southern California.The researchers looked at data from air-monitoring stations near the subjects' addresses to calculate their previous-year exposure to ozone (which forms when emissions from vehicles are exposed to sunlight), particulate matter (hazardous particles suspended in the air), and nitrous oxide (a toxic byproduct of burning fossil fuel).Of all the pollutants measured, ozone had the greatest impact on the gut by far, accounting for about 11% of the variation seen between study subjects -- more of an impact than gender, ethnicity or even diet. Those with higher exposure to ozone also had less variety of bacteria living in their gut."This is important since lower (bacteria) diversity has been linked with obesity and Type 2 diabetes," noted Alderete.Subjects with higher exposure to ozone also had a greater abundance of a specific species called Bacteroides caecimuris. That's important, because some studies have associated high levels of Bacteroides with obesty.In all, the researchers identified 128 bacterial species influenced by increased ozone exposure. Some may impact the release of insulin, the hormone responsible for ushering sugar into the muscles for energy. Other species can produce metabolites, including fatty acids, which help maintain gut barrier integrity and ward off inflammation."Ozone is likely changing the environment of your gut to favor some bacteria over others, and that can have health consequences," said Alderete.The study was relatively small and has some limitations, including the fact that stool samples were taken only once.Alderete is now moving ahead with a larger, more expansive study of young adults in the Denver area. Thanks to a new grant from the nonprofit Health Effects Institute, she's also exploring how prenatal or early-life exposure to air pollution impacts the formation of the gut microbiome in 240 infants.She said she hopes her work will ultimately influence policymakers to consider moving parks, playgrounds and housing developments away from busy roads and high pollution areas, and invest more in meeting or exceeding air quality standards."A lot of work still needs to be done, but this adds to a growing body of literature showing that human exposure to air pollution can have lasting, harmful effects on human health." | Ozone Holes | 2,020 |
February 5, 2020 | https://www.sciencedaily.com/releases/2020/02/200205084151.htm | Treating wastewater with ozone could convert pharmaceuticals into toxic compounds | With water scarcity intensifying, wastewater treatment and reuse are gaining popularity. But some methods for killing microbes in wastewater create disinfection byproducts (DBPs) that could be harmful to human health. Now researchers have found that ozone treatment and subsequent chlorination can convert trace amounts of some pharmaceuticals in wastewater into DBPs called halonitromethanes. They report their results in | The combination of ozone and chlorine kills most bacteria and viruses in wastewater. Compared with chlorine treatment alone, ozone also reduces the formation of many DBPs. Recently, however, scientists have discovered that ozone can increase the formation of potentially toxic halonitromethanes, such as chloropicrin, in chlorine-treated wastewater. Jiaming Lily Shi and Daniel McCurry wanted to determine which molecules in the wastewater were being converted to chloropricin and how.To find out, the researchers collected wastewater samples from three treatment plants in Southern California. The team discovered that ozone treatment produced nitromethane, which could have been formed from some nitrogen-containing drugs in the wastewater, including stimulants such as ephedrine and methamphetamine and certain antidepressants. Then, chlorination transformed the nitromethane into chloropricin. The pharmaceuticals, which enter wastewater through sewage, are not removed completely by conventional wastewater treatment. Future work should address how effectively processes that occur after ozone treatment can remove the nitromethane intermediate, the researchers say. | Ozone Holes | 2,020 |
February 4, 2020 | https://www.sciencedaily.com/releases/2020/02/200204112524.htm | All things considered, wooden pallets are more eco-friendly than plastic pallets | Weighing in on a debate that has raged for decades, Penn State researchers, after conducting a series of ultra-detailed comparisons, have declared that shipping pallets made of wood are slightly more environmentally friendly and sustainable than those made of plastic. | "Few people realize the significance of this issue -- there are about 700 million pallets produced and recycled each year in the United States alone," said Chuck Ray, associate professor of ecosystem science and management in the College of Agricultural Sciences. "There are 4 billion pallets in use in this country."Researchers compared the long-term performance of treated wooden and plastic pallets through a detailed, cradle-to-grave life-cycle assessment, and conducted an analysis of treatments required to kill pests such as insects. They investigated and evaluated the environmental impacts of resources consumed and emissions released by wooden and plastic pallets throughout their life cycles.In the study, the environmental impacts of the pallets were compared on a one-trip basis and 100,000-trips basis, under nine impact categories chosen by researchers because of their environmental relevance. The categories included influence on ozone layer depletion, respiratory organics, aquatic ecotoxicity, terrestrial ecotoxicity, land occupation, aquatic acidification, aquatic eutrophication, global warming and non-renewable energy.In findings published today (Feb. 3) in the "It should be noted that wooden pallets that are heat-treated to kill pests incur a carbon footprint 20% to 30% lower than those treated with methyl bromide fumigation," Ray said. "Methyl bromide gas has been blamed for depleting the Earth's ozone layer. And theoretical calculations of the resource consumption and emissions of radio-frequency treatment of pallets suggest that the new dielectric technology may provide a lower-carbon alternative to both conventionally treated wooden pallets or plastic pallets."Molded plastic pallets, typically, have a much longer life cycle than wooden pallets because plastic pallets are usually not broken or damaged and normally can travel more than 200 round trips before being taken out of service, Ray noted. Plastic pallets are made of sturdy, hardened material and are built to last longer. But they are typically derived from petroleum or natural gas products, which greatly increases their carbon footprint."What was lacking in this whole arena was a comprehensive life-cycle analysis, and that is what this study provides," Ray said. "More than a decade ago, other studies were commissioned by the wood pallet industry and by the plastic pallet industry, and of course those results favored the funders. This is the first academic, peer-reviewed study related to pallets, and it was funded entirely by Penn State and is unbiased."With current concerns about climate change and in view of the massive amount of resources consumed to make many millions of pallets, assessing their carbon footprint is important, Ray believes. With 40 percent of all hardwood produced in the United States going into pallet production, he added, it is critical to know if wooden pallets are ecologically acceptable."Because I have worked my whole career in the wood products industry, I have gained a special appreciation for the benefits of wood as an environmentally friendly product," said Ray. "The topic interests me. It did not occur to me to do this research until the plastic pallet industry started talking about their products as environmentally superior. I questioned that statement and decided to do life-cycle analyses."Also involved in the research were Sebastian Anil, now with Microsoft; Junfeng Ma, now with Mississippi State University; Gul Kremer, now with Iowa State University; and Shirin Shahidi, a graduate student in the Department of Ecosystem Science and Management when the research was conducted. | Ozone Holes | 2,020 |
January 27, 2020 | https://www.sciencedaily.com/releases/2020/01/200127134841.htm | Another reason to reduce human-made ozone: To cool a warming planet | While elected officials in the U.S. debate a proposed "Green New Deal" and U.S. President Donald Trump derides "prophets of doom" in Davos, environmental scientists continue to gather evidence about how changes to industry could mitigate the harms of climate change. | In a News and Views article in Felzer writes: "The study [by Nadine Unger et al]...assesses the effect of reducing ozone precursors in seven different economic emission sectors, the most important of which turn out to be energy (electricity and heat production from fossil fuel burning), industry (fossil fuels burned on site), road transportation and agriculture.Unger et al. ran an Earth system model, linking climate to atmospheric chemistry, to explore the global effects on photosynthesis of reducing emissions from these sectors by 50%. Ozone pollution resulted in 9-13% reductions in photosynthesis in the aforementioned polluted regions. Cleaning up ozone precursors in the transportation, energy, industrial or agricultural sectors led to 13-16% gains in photosynthesis in eastern China, and 16-23% gains in the eastern United States and Europe due to the transportation and energy sectors. Benefits were 2-3 times larger in croplands and grasslands than forests. A 50% reduction in ozone pollution from just the transportation and energy sectors resulted in an increase in photosynthesis equivalent to the amount of carbon lost by fire each year."According to Felzer, Unger and colleagues ultimately conclude that the mitigation potential resulting from addressing ozone pollution would result in a 15% increase in the size of the current land sink for carbon.From the perspective of human health impacts, there is "good" ozone and "bad" ozone. Natural ozone in the second major layer of Earth's atmosphere has a protective effect for humans, blocking the sun's harmful ultraviolet (UV) rays. Human-made ozone, a byproduct of fossil fuel production and other industrial processes, gets trapped in the atmospheric layer closest to earth and has been shown to be harmful to human health, as well as to plants, trees and crops.Human-made ozone at ground-level inhibits plant photosynthesis by directly damaging some of the plant cells responsible for it."It affects different plants differently, for example doing more damage to crops than to trees at similar doses...," he writes. "Global climate models indicate that ozone limits photosynthesis and vegetation growth in polluted regions such as the eastern United States, eastern China, and Europe...This then reduces the carbon sequestration potential of these regions..."Reducing ozone, concludes Felzer, will help vegetation to grow better and take up more Carbon Dioxide, while also reducing unhealthy pollutants such as nitrogen oxides and volatile organic compounds (VOCs).Political debates and rhetoric aside, it is a conclusion that supports reducing human-made ozone for the health of humans, as well as the planet on which all life depends. | Ozone Holes | 2,020 |
January 27, 2020 | https://www.sciencedaily.com/releases/2020/01/200127134829.htm | Cutting road transport pollution could help plants grow | Cutting emissions of particular gases could improve conditions for plants, allowing them to grow faster and capture more carbon, new research suggests. | A cocktail of gases -- including nitrogen oxides, carbon monoxide, volatile organic compounds and methane -- combines in the atmosphere to form ozone.Ozone at the Earth's surface limits photosynthesis, reducing plants' ability to grow.University of Exeter researchers say cutting emissions of ozone-forming gases offers a "unique opportunity" to create a "natural climate solution."A 50% cut in emissions of these gases from the seven largest human-made sources -- including road transport (the largest emitter) and energy production -- would help plants contribute to "negative carbon emissions," the study says."Ecosystems on land currently slow global warming by storing about 30% of our carbon dioxide emissions every year," said Professor Nadine Unger, of the University of Exeter."This carbon capture is being undermined by ozone pollution."Our findings suggest the largest losses of plant productivity are in the eastern United States, Europe and eastern China, which all have high levels of surface ozone pollution."The impact on plant growth in these areas is estimated to be 5-20% annually."Ozone is not emitted directly but forms in the atmosphere during complex chemical reactions of carbon monoxide, methane, non-methane volatile organic compounds and nitrogen oxides.The seven areas of human activity that emit the largest amounts of these gases are agriculture, residential, energy, industry, road transportation, waste/landfill and shipping.The study says a target of cutting these specific emissions by 50% is "large but plausible," citing examples of cuts already made in some industries."Deep cuts in air pollutant emissions from road transportation and the energy sector are the most effective mitigation measures for ozone-induced loss of plant productivity in eastern China, the eastern United States, Europe and globally," said Professor Unger."Our results suggest mitigation of ozone vegetation damage is a unique opportunity to contribute to negative carbon emissions, offering a natural climate solution that links fossil fuel emission abatement, air quality and climate."However, achieving these benefits requires ambitious mitigation efforts in multiple sectors." | Ozone Holes | 2,020 |
January 22, 2020 | https://www.sciencedaily.com/releases/2020/01/200122154336.htm | Despite less ozone pollution, not all plants benefit | Breathe easy: Concentrations of ozone in the air have decreased over large parts of the country in the past several decades. | But not too easy.Policies and new technologies have reduced emissions of precursor gases that lead to ozone air pollution, but despite those improvements, the amount of ozone that plants are taking in has not followed the same trend, according to Florida State University researchers. Their findings are published in the journal "Past studies of plant damage from ozone have been overly optimistic about what the improving ozone air quality means for vegetation health," said Christopher Holmes, the Werner A. and Shirley B. Baum assistant professor of meteorology in the Department of Earth, Ocean, and Atmospheric Science.Ozone is a gas made of three oxygen molecules. In the upper levels of the atmosphere, it is helpful for life on Earth because it keeps too much ultraviolet radiation from reaching the planet's surface. But when it's found at ground level, ozone is a pollutant that can damage the lungs. It's also toxic for plants, and present-day levels of the pollutant have cut global grain yields by up to 15 percent, resulting in global losses of soybean, wheat, rice and maize valued at $10 billion to $25 billion annually.The falling levels of ozone pollution are good news for human health, but FSU researchers wanted to know if plants were seeing benefits too. To answer this question, Allison Ronan, a former graduate student, and Jason Ducker, a postdoctoral researcher at FSU, worked with Holmes and another researcher to track the amount of ozone plants sucked up through pores on their leaves over 10 years at more than 30 test sites. They compared those trends to measurements of atmospheric ozone.As they expected, the ozone concentrations in the air decreased at most of their study sites, but, surprisingly, the ozone uptake into plants at the sites didn't necessarily go down at the same time. In fact, at many sites, atmospheric ozone concentrations fell while the ozone uptake into plants rose.The different trends happen because plants can open and close the stomata pores on their leaves in response to weather, especially light, temperature, moisture, drought and other environmental conditions. If the stomata close, the plants cease taking up ozone, regardless of the concentration in the surrounding air. That means the ozone uptake into leaves doesn't exactly track the amount of ozone in the air. The FSU scientists found that these environmental factors have more impact on the ozone dose the plants receive than the amount of ozone in the atmosphere."We know that weather and growing conditions vary a lot from year to year, and that variability in weather turns out to be more important for driving the trends and variability in ozone uptake into plants than the concentrations in the surrounding air," Holmes said. "With decreasing ozone concentrations, we're moving in the right direction, but the benefits for crops and vegetation may not be apparent until the air quality improvements have persisted longer."The FSU team identified the differing trends by using a dataset developed by Holmes' research group. The dataset, called SynFlux, fuses measurements from air quality networks with data from field sites that monitor energy flows between vegetation and the atmosphere. It enabled the team to study ozone uptake trends at many more sites than has previously been possible.Future studies of plant damage and accompanying economic losses need to avoid relying primarily on measures of ozone concentration in the atmosphere and look at ozone uptake instead, researchers said."With the SynFlux dataset that we have developed, we've now got the information to do that on a large scale at many sites across multiple continents," Holmes said. "We're just scratching the surface of what we can learn about air pollution impacts on vegetation using this tool."Jordan L. Schnell at Northwestern University contributed to this research. This work was supported by the Winchester Fund at Florida State University, NASA and the National Science Foundation. | Ozone Holes | 2,020 |
January 21, 2020 | https://www.sciencedaily.com/releases/2020/01/200121112911.htm | Brazilian wildfire pollution worsens air quality in distant cities | Wildfires in south eastern Brazil produce airborne pollution that worsens air quality in major cities such as Sao Paulo -- cancelling out efforts to improve the urban environment and posing health risks to citizens, according to a new study. | The planet is frequently affected by smoke from fires caused by humans and natural processes. Australia, California and other regions are prone to seasonal wildfires and smoke from wildfires and agricultural burns worsening air quality in places up to 2,000?km away.Most wildfires in Brazil occur in the dry season between July and September in the areas of Amazon and Cerrado -- mostly agriculture-related fires -- and the Pampas. Depending on the weather, long-range transport of smoke affects the air quality of small and large cities downwind of the fire spots, including the 'megacity' of Sao Paulo.Burning biomass produces increased quantities of low-lying ozone due, in part, to the South Atlantic subtropical high pressure system. Transported considerable distances from the fire, this pollution further contribute to poor air quality and smog in cities such as Sao Paulo.Researchers from the University of Birmingham, the Federal University of Technology, Londrina, Brazil, and the University of Stockholm published their findings in the Professor Roy Harrison, from the University of Birmingham, commented: "The state of Sao Paulo has led with progressive measures to curb air pollution, such as controlling sulphur dioxide from industrial sources and enforcing standards for cleaner vehicles and fuels."However, present results indicate that policies targeting the reduction of biomass burning are of utmost importance to improve urban air quality, particularly in densely populated areas where high pollutant concentrations are frequently observed."Besides affecting air quality and increasing the risk of death from respiratory causes, ozone is a short-lived climate forcer -- an atmospheric compound with a warming effect but with a shorter lifetime than carbon dioxide. Reducing ozone levels has two main benefits: reducing impact on air quality and climate.Atmospheric emission data suggests that emissions from biomass burning make up a substantial part of the precursors for O3 formation.Dr. Admir Créso Targino, from the Federal University of Technology, commented: "We need enhanced governance at regional, national and international levels to combat biomass burning practices in Brazil and its neighbouring countries."Not only would the population health benefit from such a measure, but also the regional climate, as ozone and particulate matter generated by the fires are short-lived climate forcers. Such an approach would be well-aligned with the Paris Agreement that aims to limit global warming to below 2OC compared to the pre-industrial period -- a critical measure in the fight against climate change."Researchers combined in situ ozone data, measured in the states of Sao Paulo and Parana from 2014 to 2017, with information about a range of co-pollutants such as NOx, PM2.5 and PM10 to identify sources, transport and geographical patterns in the air pollution data.Ozone concentrations peaked in September and October -- linked to biomass burning and enhanced photochemistry. Long-range transport of smoke contributed to between 23 and 41 per cent of the total ozone during the pollution events. | Ozone Holes | 2,020 |
January 13, 2020 | https://www.sciencedaily.com/releases/2020/01/200113153310.htm | Iodine may slow ozone layer recovery | A new paper quantifying small levels of iodine in Earth's stratosphere could help explain why some of the planet's protective ozone layer isn't healing as fast as expected. | The paper posits a set of connections that link air pollution near Earth's surface to ozone destruction much higher in the atmosphere. That higher-level ozone protects the planet's surface from radiation that can cause skin cancer and damage crops."The impact is maybe 1.5 to 2 percent less ozone," said lead author Theodore Koenig, a postdoctoral researcher at CIRES and the University of Colorado Boulder, referring to ozone in the lower part of the ozone layer, around Earth's tropics and temperate zones. "That may sound small, but it's important," he said.A slightly thinner ozone layer means more UVB radiation can get through to Earth's surface.Koenig's paper, the first "quantitative detection" of iodine in the stratosphere, is published this week in the Chemicals once used widely in refrigeration, spray cans and solvents can eat away at Earth's ozone layer. After scientists discovered the stratospheric "ozone hole" in the 1980s, nations around the world signed the international Montreal Protocol agreement to protect the ozone layer, limiting the emission of ozone-depleting chemicals."The ozone layer is starting to show early signs of recovery in the upper stratosphere, but ozone in the lower stratosphere continues to decline for unclear reasons," said Rainer Volkamer, a CIRES Fellow, CU Boulder professor of chemistry and corresponding author of the new assessment."Before now, the decline was thought to be due to changes in how air mixes between the troposphere and stratosphere. Our measurements show there is also a chemical explanation, due to iodine from oceans. What I find exciting is that iodine changes ozone by just enough to provide a plausible explanation for why ozone in the lower stratosphere continues to decline."For the new work, Volkamer and his colleagues pored through data from several recent atmospheric research campaigns involving U.S. National Science Foundation (NSF) and NASA research aircraft, and which included instruments that could pick up tiny amounts of iodine and other so-called halogens in the lower stratosphere during the daytime. Halogens, which also include chlorine and bromine, are key to ozone destruction.It's been tricky to get data from this part of the atmosphere, Koenig said. "We knew there was some iodine there, but we couldn't pin numbers on it until now... This is a result of technological advancement: Our instruments just kept getting a little bit better and eventually, it was enough to make measurements."The amount of iodine they picked up in the lower stratosphere is tiny, similar to adding a few bottles of water to the Great Salt Lake. But iodine is extremely effective at destroying ozone, and, generally speaking, the amount the scientists measured is enough to explain the level of ozone destruction in the lower stratosphere.So where did the iodine come from? Strangely it seems to be a result of air pollution down here at the surface of the planet, the new assessment reports.Ozone at Earth's surface is a pollutant, one that is regulated in the United States and elsewhere because it can harm people's lungs. And when ozone pollution interacts chemically with the surface of oceans, it can "pull" naturally occurring iodine up into the atmosphere. Other studies have shown that in the lower atmosphere, iodine levels have roughly tripled in concentration since 1950.Some of that iodine is apparently making it up into the stratosphere, where it can trigger ozone depletion, Koenig said. "This should not diminish the success story of the Montreal Protocol, but still, it is important. The lower stratosphere should have improved already, not gotten worse.""There's something going on resulting in deterioration. Our hypothesis is that ozone at the surface is destroying ozone in the stratosphere," Koenig added.It will be important to study the hypothesis in greater detail, Koenig and his coauthors said. If ozone pollution at Earth's surface increases, for example, could it trigger even more lower-stratosphere ozone layer destruction?Coauthor Pedro Campuzano-Jost, a CIRES research associate, said the success of the research project is partly due to the unique scope of NASA's ATom (Atmospheric Tomography) mission, which flew a research aircraft across the globe; and NSF's CONTRAST (Convective Transport of Active Species in the Tropics) mission, which detected iodine oxide radicals in the stratosphere."Half of the places we went had never been sampled before for aerosols," Campuzano-Jost said, and that is the kind of opportunity that leads to new discoveries.Volkamer and his colleagues hope to successfully pitch a new mission to study iodine chemistry in greater detail, to better understand the future of Earth's protective ozone layer. | Ozone Holes | 2,020 |
January 6, 2020 | https://www.sciencedaily.com/releases/2020/01/200106141445.htm | Shutdown of coal-fired plants in US saves lives and improves crop yields | The decommissioning of coal-fired power plants in the continental United States has reduced nearby pollution and its negative impacts on human health and crop yields, according to a new University of California San Diego study. | The findings published this week in The author, Jennifer Burney, associate professor of environmental science at the UC San Diego School of Global Policy and Strategy, combined data from the Environmental Protection Agency (EPA) on electric power generation with satellite and surface measurements from the EPA as well as NASA to gauge changes in local pollution before and after coal-fired unit shut-downs. She also studied changes in county-level mortality rates and crop yields using data from the Centers for Disease Control and the U.S. Department of Agriculture.Burney found that between 2005 and 2016, the shutdown of coal-fired units saved an estimated 26,610 lives and 570 million bushels of corn, soybeans and wheat in their immediate vicinities. The inverse calculation, estimating the damages caused by coal plants left in operation over that same time period, suggests they contributed to 329,417 premature deaths and the loss of 10.2 billion bushels of crops, roughly equivalent to half of year's typical production in the U.S."The unique contribution of this study is its scope and the ability to connect discrete technology changes -- like an electric power unit being shut down -- to local health, agriculture and regional climate impacts," Burney said. "We hear a lot about the overall greenhouse gas and economic impacts of the transition the U.S. has undergone in shifting from coal towards natural gas, but the smaller-scale decisions that make up this larger trend have really important local consequences. The analysis provides a framework for communities to more thoroughly and accurately assess the costs and benefits of local investments in energy infrastructure."Burney added that although there are considerable benefits of decommissioning older coal-fired units, the newer natural gas units are not entirely benign. Natural gas units are associated with increased pollution levels; although different than the pollutant mix from coal-fired units, and more research is required to fully understand their impacts.Burney concludes that "policymakers often think about greenhouse gas emissions as a separate problem from air pollution, but the same processes that cause climate change also produce these aerosols, ozone, and other compounds that cause important damages. This study provides a more robust accounting for the full suite of emissions associated with electric power production. If we understand the real costs of things like coal better, and who is bearing those costs, it could potentially lead to more effective mitigation and formation of new coalitions of beneficiaries across sectors." | Ozone Holes | 2,020 |
December 16, 2019 | https://www.sciencedaily.com/releases/2019/12/191216132023.htm | Planetary boundaries: Interactions in Earth system amplify human impacts | What we do to one part of our Earth system does not just add to what we do to other parts: "We found a dense network of interactions between the planetary boundaries," says Johan Rockström, Director of the Potsdam Institute for Climate Impact Research and co-author of the study. Two core boundaries -- climate change and biosphere integrity -- contribute more than half the combined strengths of all the interactions in that network, the scientists find. "This highlights how careful we should be in destabilizing these two," says Rockström. "The resulting cascades and feedbacks amplify human impacts on the Earth system and thereby shrink the safe operating space for our children and grand-children." | Burning down tropical forests to expand agricultural lands for instance increases the amount of CO2 in the atmosphere. The additional greenhouse gases contribute to the global temperature increase, the harm done to the forests becomes harm to climate stability. The temperature increase can in turn further enhance stress on tropical forests, and for agriculture. The resulting amplification of effects is substantial even without taking tipping points into account: Beyond a certain threshold, the Amazon rainforest might show rapid, non-linear change. Yet such a tipping behavior would come on top of the amplification highlighted in the analysis now published.The new study builds on the groundbreaking 2009 and 2015 studies on the planetary boundaries framework that identified the nine critical systems that regulate the state of the planet: climate change, biogeochemical flows (namely of nitrogen and phosphorus), land-system change, freshwater use, aerosol loading, ozone depletion, ocean acidification, loss of biosphere integrity including biodiversity, and introductions of novel entities such as toxic chemicals and plastics. The way of staying within planetary boundaries varies from one place to another on Earth, hence calculating them and the interactions between them on an aggregated level cannot directly be translated into policies. Yet it can provide some guidance."There's good news for policy-makers in our findings," concludes Rockström. "If we reduce our pressure on one planetary boundary, this will in many cases also lessen the pressure on other planetary boundaries. Sustainable solutions amplify their effects -- this can be a real win-win." | Ozone Holes | 2,019 |
November 18, 2019 | https://www.sciencedaily.com/releases/2019/11/191118162932.htm | Nitrous oxide, a greenhouse gas, is on the rise | Most of us know nitrous oxide as "laughing gas," used for its anaesthetic effects. But nitrous oxide (N | "We see that the NIncreasing use of nitrogen fertilizers is leading to higher NIn the study, Thompson and scientists including Eric Davidson of the University of the Maryland Center for Environmental Science found that nitrous oxide in the atmosphere has risen steadily since the mid-20th century. This rise is strongly linked to an increase in nitrogen substrates released to the environment. Since the mid-20th century, the production of nitrogen fertilizers, widespread cultivation of nitrogen-fixing crops (such as clover, soybeans, alfalfa, lupins, and peanuts), and the combustion of fossil and biofuels has increased enormously the availability of nitrogen substrates in the environment."The increased nitrogen availability has made it possible to produce a lot more food," Thompson said. "The downside is of course the environmental problems associated with it, such as rising NThe study authors found that N"This new publication demonstrates both how we can solve a problem of growing greenhouse gas emissions and how current efforts are falling short in some regions of the world," said co-author Eric Davidson of the University of Maryland Center for Environmental Science. "These emissions come primarily from using fertilizers to grow food and increasing livestock herds, but we've learned how to produce more food with less nitrous oxide emission.""In Europe and North America, we have succeeded in decreasing growth in nitrous oxide emissions, an important contributor to climate change and stratospheric ozone depletion," he added. "Unfortunately, the same can't be said for Asia and South America, where fertilizer use, intensification of livestock production, and the resulting nitrous oxide emissions are growing rapidly."The good news is that this problem can be solved, but the less good news is that it will take a global effort, and we are far from there yet," he said. | Ozone Holes | 2,019 |
October 29, 2019 | https://www.sciencedaily.com/releases/2019/10/191029131458.htm | New AI deep learning model allows earlier, more accurate ozone warnings | Researchers from the University of Houston have developed an artificial intelligence-based ozone forecasting system, which would allow local areas to predict ozone levels 24 hours in advance. | That would improve health alerts for people at heightened risk of developing problems because of high ozone levels.Yunsoo Choi, associate professor in the Department of Earth and Atmospheric Sciences and corresponding author for a paper explaining the work, said they built an artificially intelligent model using a convolutional neural network, which is able to take information from current conditions and accurately predict ozone levels for the next day. The work was published in the journal "If we know the conditions of today, we can predict the conditions of tomorrow," Choi said.Ozone is an unstable gas, formed by a chemical reaction when sunlight combines with nitrogen oxides (NOx) and volatile organic compounds, both of which are found in automobile and industrial emissions. It can cause respiratory problems in people, and those especially susceptible to ozone -- including people with asthma, the elderly and young children -- are advised to reduce their exposure when ozone levels are high.Alqamah Sayeed, first author on the paper and a Ph.D. student in Choi's Air Quality Forecasting and Modeling Lab, said most current ozone forecasting models don't incorporate artificial intelligence and can take several hours to predict future ozone levels, rather than just a few seconds for the new model. They also are less accurate; the researchers reported their model correctly predicted ozone levels 24 hours in advance between 85% and 90% of the time.A key difference, Choi said, is the use of convolutional neural networks, networks capable of "sweeping" data and using that to form assumptions based on what it has learned. The convolutional networks are generally used to improve imaging resolution, he said. Choi and Sayeed said using the networks to extract information and then using artificial intelligence in order to make predictions from that data is a new application, illustrating the strength of the networks' ability to gather information and make inferences based upon that information.The researchers used meteorological and air pollution data collected at 21 stations in Houston and elsewhere in Texas by the Texas Commission on Environmental Quality, representing conditions between 2014 and 2017. Sayeed said they programmed the convolutional neural networks using meteorological data -- temperature, barometric pressure, wind speed and other variables -- for each day, and added ozone measurements from each station for 2014, 2015 and 2016.To test their belief that the model would be able to predict ozone levels given meteorological conditions from the previous day, they added weather data for 2017 and checked the forecasts the network produced for accuracy.The model's forecasts reached 90% accuracy, and Choi said it will become more accurate over time, as the network continues to learn.Although the tests were done using Texas data, the researchers said the model could be used anywhere in the world. "The U.S. is geographically different from East Asia," Choi said, "but the physics and chemistry of ozone creation are the same."Sayeed said the researchers are currently working to expand the model to include predictions of other types of pollutants, including particulate matter, as well as to extend the time period beyond 24 hours. | Ozone Holes | 2,019 |
October 25, 2019 | https://www.sciencedaily.com/releases/2019/10/191025113017.htm | Energy regulation rollbacks threaten progress against harmful ozone | Pollutants from coal-fired power plants help make ground-level ozone, and a warming world exacerbates that. Recent rollbacks of U.S. energy regulations may speed climate change, keep pollutants coming, and thus slow the fight against harmful ozone, according to a new study to be published Friday. | Currently, 30 percent of the U.S. population lives with ozone levels that exceed government health standards. Though past environmental regulations have vastly helped clean the air and put the U.S. on a positive trajectory to reduce pollutants -- including ozone -- policy rollbacks back could slow the progress then reverse it, researchers from the Georgia Institute of Technology said.Continuing progress against ozone would pay off in better health and finances: The more ozone in the air, the more cases of respiratory illness and the higher the cost of meeting ozone level targets."Additional ozone is tough to control technologically. The costs would be very high -- tens of billions of dollars," said Ted Russell, a principal investigator on the study. "In the meantime, more people would die than otherwise would have."The researchers will publish their results in The study focuses on ground-level ozone people breathe to the detriment of their health, which should not be confused with the stratospheric ozone that protects us from the sun's harmful radiation.In the last three years, various energy policies have been loosened, which should result in raised CO"Incentives are being retired like production and investment tax credits, which have been very influential in solar and wind," said Marilyn Brown, a Regents professor in Georgia Tech's School of Public Policy and a principal investigator on the study. "The Investment Tax Credit gives a 30 percent tax reduction for investments in solar or wind farms or the purchase of solar rooftop panels by homeowners. The Production Tax Credit for utilities reduces tax liabilities by 23 cents for each kilowatt-hour of electricity generated by solar, wind or other renewable energy sources."But one policy move in particular stands to keep more ingredients in the ozone-making cauldron: courts preventing the Clean Power Plan (CPP) from going into effect and its replacement with the Trump administration's Affordable Clean Energy (ACE) plan.ACE, which also has not been implemented, would make it easier to continue burning fossil fuels, particularly coal, according to Brown, who was a member of the Intergovernmental Panel on Climate Change, which received a Nobel Peace Prize in 2007. CPP would have phased out those generators, reducing nitrogen oxide gases, or NOX, key reactants in the production of ozone."The major target of the CPP was CO2, but it had side effects on the reduction of NOX because it shifted coal use to natural gas as well as to renewable sources," said Huizhong Shen, a postdoctoral researcher in Russell's group and one of the study's first authors.The study modeled atmospheric chemistry that produces O3 around commonly predicted trajectories for greenhouse gas emissions and climate change paired with anticipated pollutant emissions, particularly of NOX. The model's output depicted "non-attainment" scores, which refer to the number of U.S. counties exceeding ozone targets and by how much.The study modeled against official targets for ozone levels and in addition, against cleaner standards widely held to be attainable and much healthier for people. Models built around rolled-back environmental regulations and increased warming initially showed the current trajectory of progress against ozone levels continuing -- but later reversing. Ozone levels then rose again, putting many more counties in non-attainment by or before 2050.Alongside human-produced NOX, nature contributes ozone-making ingredients that aren't harmful per se and often smell great, like the aroma of cut grass or of a pine tree. They are examples of volatile organic compounds (VOCs), of which nature produces hundreds.VOCs get into the air easily and react readily with other chemicals. The warmer the air and the sun, the more vegetation produces VOCs that meet with raised levels of NOX emissions to make ozone. It forms downstream from emissions sources, making it hard to regulate."There are no ozone emissions, just precursor emissions," Shen said. "So, emission controls for ozone have to mainly target NOX emissions."Keeping ozone around as the world warms will be more than just the sum of power plants still emitting NOX plus boosted VOC emissions."If you heat up the air, it also speeds up photochemical reactions involved in ozone production," Shen said."Ozone is a greenhouse gas, so it adds some climate change feedback, too," said Russell, who is Howard T. Tellepsen Chair and Regents Professor in Georgia Tech's School of Civil and Environmental Engineering. "You can also have increased vegetation emissions of ammonia. Some of this goes on to form particulate matter, which is also harmful to the lungs."When coal-fired power plants emit NOX, the ozone strikes miles away."Ozone can occur hundreds of miles away, so if controls are loosened in one state to save industry money there, a state downstream may have to spend even more to try to meet ozone targets. You transfer the problem and the costs," Russell said. "Most U.S. cities are already not in attainment, and this will likely make it harder for them to get there."The research was funded by the U.S. Environmental Protection Agency and by the National Science Foundation. | Ozone Holes | 2,019 |
October 3, 2019 | https://www.sciencedaily.com/releases/2019/10/191003162541.htm | How much are you polluting your office air just by existing? | Just by breathing or wearing deodorant, you have more influence over your office space than you might think, a growing body of evidence shows. But could these basic acts of existence also be polluting the air in the office room where you work? | To find out, a team of engineers at Purdue University has been conducting one of the largest studies of its kind in the office spaces of a building rigged with thousands of sensors. The goal is to identify all types of indoor air contaminants and recommend ways to control them through how a building is designed and operated."If we want to provide better air quality for office workers to improve their productivity, it is important to first understand what's in the air and what factors influence the emissions and removal of pollutants," said Brandon Boor, an assistant professor of civil engineering with a courtesy appointment in environmental and ecological engineering.The data is showing that people and ventilation systems greatly impact the chemistry of indoor air -- possibly more than anything else in an office space. The researchers will present their initial findings at the 2019 American Association for Aerosol Research Conference in Portland, Oregon, Oct. 14-18."The chemistry of indoor air is dynamic. It changes throughout the day based on outdoor conditions, how the ventilation system operates and occupancy patterns in the office," Boor said.The building, called the Living Labs at Purdue's Ray W. Herrick Laboratories, uses an array of sensors to precisely monitor four open-plan office spaces and to track the flow of indoor and outdoor air through the ventilation system. The team developed a new technique to track occupancy by embedding temperature sensors in each desk chair.Through use of the Living Labs, Boor's team has begun to identify previously unknown behaviors of chemicals called volatile organic compounds, such as how they are transformed in ventilation systems and removed by filters."We wanted to shed light on the behind-the-scenes role ventilation systems have on the air we breathe," Boor said.Boor teamed up with researchers at RJ Lee Group to deploy a highly sensitive "nose" -- an instrument that scientists call a proton transfer reaction time-of-flight mass spectrometer. The instrument, typically used for measuring outdoor air quality, helped "sniff" out compounds in human breath, such as isoprene, in real time. Boor's team found that isoprene and many other volatile compounds linger in the office even after people have left the room.A greater number of people in a room also means more emissions of these compounds. A YouTube video is available at "Our preliminary results suggest that people are the dominant source of volatile organic compounds in a modern office environment," Boor said. "We found levels of many compounds to be 10 to 20 times higher indoors than outdoors. If an office space is not properly ventilated, these volatile compounds may adversely affect worker health and productivity."The team also revealed that a pollutant entering from outside, ozone, disappears inside. This is because ozone interacts with other indoor compounds and the vast surfaces of a furnished office. The researchers found that ozone and compounds released from peeling an orange, called monoterpenes, mix to form new, super-tiny particles as small as one-billionth of a meter. The newly formed particles could be toxic because they are small enough to get into the deepest regions of a person's lungs.The effects of volatile compounds released in an office might not just be restricted to indoors. The researchers believe that chemicals emitted from self-care products such as deodorant, makeup, and hair spray may elevate levels outdoors as they are vented outside by the ventilation system.This work is funded in part by the National Science Foundation Environmental Engineering Program, the Alfred P. Sloan Foundation Chemistry of Indoor Environments Program and the Purdue Research Foundation. | Ozone Holes | 2,019 |
October 1, 2019 | https://www.sciencedaily.com/releases/2019/10/191001083959.htm | Rising ozone is a hidden threat to corn | Like atmospheric methane and carbon dioxide, ground-level ozone is on the rise. But ozone, a noxious chemical byproduct of fossil fuel combustion, has received relatively little attention as a potential threat to corn agriculture. | A new study begins to address this lapse by exposing a genetically diverse group of corn plants in the field to future ozone levels. The study, reported in the journal "Ozone enters plants the same way carbon dioxide does: It diffuses from the atmosphere into the leaf," said Lisa Ainsworth, a U.S. Department of Agriculture scientist who led the research with University of Illinois plant biology professor Andrew Leakey; University of Florida molecular genetics and microbiology professor Lauren McIntyre; and University of California, Davis plant sciences professor Patrick Brown. Ainsworth and Leakey are affiliates of the Carl R. Woese Institute for Genomic Biology and the department of crop sciences at Illinois.Carbon dioxide is a nutrient for plants, Ainsworth said. "All the carbon that ends up in the grain comes through the leaf first," she said. But ozone is a highly reactive molecule that damages biological tissues and impairs photosynthetic carbon capture in plant leaves."Basically, ozone accelerates the aging of the leaf," Leakey said.Even background levels of ozone do some damage, Ainsworth said. "Our research suggests that current ozone levels decrease corn yields by as much as 10%," she said. "That's as much as drought or flooding or any single pest or disease, but this is a relatively unstudied component of yield loss in the U.S."The researchers used the Free Air Concentration Enrichment facility at the U. of I. to track the real-world consequences of higher atmospheric ozone levels in an agricultural field. The FACE facility uses a sophisticated emission system that monitors wind direction and speed to dose a field with specific levels of a variety of gases, including ozone."The level that we're fumigating to in this study is a level that is commonly found today in China and India," Ainsworth said. "So, it's not excessively high, even though we're using a concentration that is 2 1/2 times the level of background ozone in central Illinois."The researchers planted 45 hybrid corn plants representing all the major types of corn -- popcorn, broom corn, dent, flint and others -- to look for variation in their responses to high ozone levels. They found that some hybrids were more sensitive to ozone stress than others."We found two maize lines whose offspring were more sensitive to ozone pollution, regardless of which other types of corn we bred them with," Leakey said. "Their genetic deficiencies manifested in different ways when exposed to the high ozone conditions."The genetics of commercial corn are a trade secret, so "we don't know if these corn varieties have the same Achilles' heels," Leakey said. "Breeders would not know about these differences since they are not apparent under clean-air conditions."More genetic analysis and more experiments like those conducted at the FACE facility will be needed to determine how today's plants will respond to future conditions, Leakey said."It's important to understand how plants are going to respond to climate change before the climate changes," he said. "That is the only way we can find the solutions that will be needed in the future." | Ozone Holes | 2,019 |
September 18, 2019 | https://www.sciencedaily.com/releases/2019/09/190918100230.htm | Emissions from cannabis growing facilities may impact indoor and regional air quality | The same chemicals responsible for the pungent smell of a cannabis plant may also contribute to air pollution on a much larger scale, according to new research from the Desert Research Institute (DRI) and the Washoe County Health District (WCHD) in Reno, Nev. | In a new pilot study, DRI scientists visited four cannabis growing facilities in Nevada and California to learn about the chemicals that are emitted during the cultivation and processing of cannabis plants, and to evaluate the potential for larger-scale impacts to urban air quality.At each facility, the team found high levels of strongly-scented airborne chemicals called biogenic volatile organic compounds (BVOCs), which are naturally produced by the cannabis plants during growth and reproduction. At facilities where cannabis oil extraction took place, researchers also found very high levels of butane, a volatile organic compound (VOC) that is used during the oil extraction process."The concentrations of BVOCs and butane that we measured inside of these facilities were high enough to be concerning," explained lead author Vera Samburova, Ph.D., Associate Research Professor of atmospheric science at DRI. "In addition to being potentially hazardous to the workers inside the cannabis growing and processing facilities, these chemicals can contribute to the formation of ground-level ozone if they are released into the outside air."Although ozone in the upper atmosphere provides protection from UV rays, ozone at ground-level is a toxic substance that is harmful for humans to breathe. Ozone can be formed when volatile organic compounds (including those from plants, automobile, and industrial sources) combine with nitrogen oxide emissions (often from vehicles or fuel combustion) in the presence of sunlight. All of these ozone ingredients are in ample supply in Nevada's urban areas, Samburova explained -- and that impacts our air quality."Here in our region, unfortunately, we already exceed the national air quality standard for ground-level ozone quite a few times per year," Samburova said. "That's why it is so important to answer the question of whether emissions from cannabis facilities are having an added impact."At one of the four cannabis growing facilities visited during this study, the team measured emission rates over time, to learn about the ozone-forming potential of each individual plant. The results show that the BVOCs emitted by each cannabis plant could trigger the formation of ground-level (bad) ozone at a rate of approximately 2.6g per plant per day. The significance of this number is yet to be determined, says Samurova, but she and her team feel strongly that their findings have raised questions that warrant further study."This really hasn't been studied before," Samburova said. "We would like to collect more data on emissions rates of plants at additional facilities. We would like to take more detailed measurements of air quality emissions outside of the facilities, and be able to calculate the actual rate of ozone formation. We are also interested in learning about the health impacts of these emissions on the people who work there."The cannabis facility personnel that the DRI research team interacted with during the course of the study were all extremely welcoming, helpful, and interested in doing things right, Samburova noted. Next, she and her team hope to find funding to do a larger study, so that they can provide recommendations to the growing facilities and WCHD on optimum strategies for air pollution control."With so much growth in this industry across Nevada and other parts of the United States, it's becoming really important to understand the impacts to air quality," said Mike Wolf, Permitting and Enforcement Branch Chief for the WCHD Air Quality Management Division. "When new threats emerge, our mission remains the same: Implement clean air solutions that protect the quality of life for the citizens of Reno, Sparks, and Washoe County. We will continue to work with community partners, like DRI, to accomplish the mission." | Ozone Holes | 2,019 |
August 28, 2019 | https://www.sciencedaily.com/releases/2019/08/190828140132.htm | Earth's fingerprint hints at finding habitable planets beyond the solar system | Two McGill University astronomers have assembled a "fingerprint" for Earth, which could be used to identify a planet beyond our Solar System capable of supporting life. | McGill Physics student Evelyn Macdonald and her supervisor Prof. Nicolas Cowan used over a decade of observations of Earth's atmosphere taken by the SCISAT satellite to construct a transit spectrum of Earth, a sort of fingerprint for Earth's atmosphere in infrared light, which shows the presence of key molecules in the search for habitable worlds. This includes the simultaneous presence of ozone and methane, which scientists expect to see only when there is an organic source of these compounds on the planet. Such a detection is called a "biosignature.""A handful of researchers have tried to simulate Earth's transit spectrum, but this is the first empirical infrared transit spectrum of Earth," says Prof. Cowan. "This is what alien astronomers would see if they observed a transit of Earth."The findings, published Aug. 28 in the journal Cowan was explaining transit spectroscopy of exoplanets at a group lunch meeting at the McGill Space Institute (MSI) when Prof. Yi Huang, an atmospheric scientist and fellow member of the MSI, noted that the technique was similar to solar occultation studies of Earth's atmosphere, as done by SCISAT.Since the first discovery of an exoplanet in the 1990s, astronomers have confirmed the existence of 4,000 exoplanets. The holy grail in this relatively new field of astronomy is to find planets that could potentially host life -- an Earth 2.0.A very promising system that might hold such planets, called TRAPPIST-1, will be a target for the upcoming James Webb Space Telescope, set to launch in 2021. Macdonald and Cowan built a simulated signal of what an Earth-like planet's atmosphere would look like through the eyes of this future telescope which is a collaboration between NASA, the Canadian Space Agency and the European Space Agency.The TRAPPIST-1 system located 40 light years away contains seven planets, three or four of which are in the so-called "habitable zone" where liquid water could exist. The McGill astronomers say this system might be a promising place to search for a signal similar to their Earth fingerprint since the planets are orbiting an M-dwarf star, a type of star which is smaller and colder than our Sun."TRAPPIST-1 is a nearby red dwarf star, which makes its planets excellent targets for transit spectroscopy. This is because the star is much smaller than the Sun, so its planets are relatively easy to observe," explains Macdonald. "Also, these planets orbit close to the star, so they transit every few days. Of course, even if one of the planets harbours life, we don't expect its atmosphere to be identical to Earth's since the star is so different from the Sun."According to their analysis, Macdonald and Cowan affirm that the Webb Telescope will be sensitive enough to detect carbon dioxide and water vapour using its instruments. It may even be able to detect the biosignature of methane and ozone if enough time is spent observing the target planet.Prof. Cowan and his colleagues at the Montreal-based Institute for Research on Exoplanets are hoping to be some of the first to detect signs of life beyond our home planet. The fingerprint of Earth assembled by Macdonald for her senior undergraduate thesis could tell other astronomers what to look for in this search. She will be starting her Ph.D. in the field of exoplanets at the University of Toronto in the Fall. | Ozone Holes | 2,019 |
August 13, 2019 | https://www.sciencedaily.com/releases/2019/08/190813180833.htm | Air pollution can accelerate lung disease as much as a pack a day of cigarettes | Air pollution -- especially ozone air pollution which is increasing with climate change -- accelerates the progression of emphysema of the lung, according to a new study led by the University of Washington, Columbia University and the University at Buffalo. | While previous studies have shown a clear connection of air pollutants with some heart and lung diseases, the new research published Aug. 13 in "We were surprised to see how strong air pollution's impact was on the progression of emphysema on lung scans, in the same league as the effects of cigarette smoking, which is by far the best-known cause of emphysema," said the study's senior co-author, Dr. Joel Kaufman, UW professor of environmental and occupational health sciences and epidemiology in the School of Public Health.In fact, the researchers found, if the ambient ozone level was 3 parts per billion higher where you live compared to another location over 10 years, that was associated with an increase in emphysema roughly the equivalent of smoking a pack of cigarettes a day for 29 years. And the study determined that ozone levels in some major U.S. cities are increasing by that amount, due in part to climate change. The annual averages of ozone levels in study areas were between about 10 and 25 ppb."Rates of chronic lung disease in this country are going up and increasingly it is recognized that this disease occurs in nonsmokers," said Kaufman, also a professor of internal medicine and a physician at UW School of Medicine. "We really need to understand what's causing chronic lung disease, and it appears that air pollution exposures that are common and hard to avoid might be a major contributor."The results are based on an extensive, 18-year study involving more than 7,000 people and a detailed examination of the air pollution they encountered between 2000 and 2018 in six metropolitan regions across the U.S.: Chicago, Winston-Salem, N.C., Baltimore, Los Angeles, St. Paul, Minnesota, and New York. The participants were drawn from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung studies."To our knowledge, this is the first longitudinal study to assess the association between long-term exposure to air pollutants and progression of percent emphysema in a large, community-based, multi-ethnic cohort," said first author Meng Wang, an assistant professor of epidemiology and environmental health at the University at Buffalo who conducted the research as a postdoctoral researcher at the UW.The authors developed novel and accurate exposure assessment methods for air pollution levels at the homes of study participants, collecting detailed measurement of exposures over years in these metropolitan regions, and measurements at the homes of many of the participants. This work in the MESA Air study was led at the University of Washington. While most of the airborne pollutants are in decline because of successful efforts to reduce them, ozone has been increasing, the study found. Ground-level ozone is mostly produced when ultraviolet light reacts with pollutants from fossil fuels."This is a big study with state-of-the-art analysis of more than 15,000 CT scans repeated on thousands of people over as long as 18 years. These findings matter since ground-level ozone levels are rising, and the amount of emphysema on CT scans predicts hospitalization from and deaths due to chronic lung disease," said Dr. R. Graham Barr, professor of medicine and epidemiology at Columbia University who led the MESA Lung study and is a senior author of the paper."As temperatures rise with climate change," Barr explained, "ground-level ozone will continue to increase unless steps are taken to reduce this pollutant. But it's not clear what level of the air pollutants, if any, is safe for human health."Emphysema was measured from CT scans that identify holes in the small air sacs of the participants' lungs, and lung function tests, which measure the speed and amount of air breathed in and out."This study adds to growing evidence of a link between air pollution and emphysema. A better understanding of the impact of pollutants on the lung could lead to more effective ways of preventing and treating this devastating disease," said James Kiley, director of the Division of Lung Diseases at the National Heart, Lung, and Blood Institute, part of the National Institutes of Health."It's important that we continue to explore factors that impact emphysema," Kiley added, "particularly in a large, well-characterized multi-ethnic group of adults such as those represented by MESA." | Ozone Holes | 2,019 |
July 25, 2019 | https://www.sciencedaily.com/releases/2019/07/190725100519.htm | Reducing greenhouse gas in rocky mountain region has health, financial benefits | Research by Drexel University and the University of Colorado at Boulder suggests that imposing fees on energy producers that emit greenhouse gas could improve the health and financial well-being of the Rocky Mountain region. | Using sophisticated modeling programs that can project atmospheric concentrations of ozone, a ground-level pollutant, by considering factors like current emissions from power plants, weather trends and changes in energy production, the team compared the effects of four scenarios on the Rocky Mountain region of 2030. Their findings were recently published in the journal Looking closely at coal, oil and natural gas production regions in Colorado, Utah, Wyoming and northern New Mexico -- a region in the midst of planning its energy production transition over the next several decades -- the team proposed four energy production policy scenarios, any of which could very well be in effect by 2030."Opportunities to produce power through newly accessible oil and gas as well as renewable resources have increased rapidly in the Rocky Mountain region, which has a growing population," said Shannon Capps, PhD, an assistant professor in Drexel's College of Engineering who helped conduct the research. "The region needs more electricity and has choices about how to produce it. This analysis helps people understand the implications of different choices, some imbedded in infrastructure that will shape climate and air quality in lasting ways."The first is a baseline scenario in which current transitions away from coal energy and toward natural gas, including the planned closing of several coal plants and the creation of new natural gas extraction sites, are taken into consideration.Two scenarios consider the effects of changes in the cost of energy production from natural gas -- either that it will be more expensive to produce than coal or that it will continue to be less expensive.The final scenario considers the possibility of fees being imposed on the producers of greenhouse gas -- a policy that has been proposed by the previous administration's Clean Power Plan and proponents of the Green New Deal.The group used recent results from energy grid modeling under the different scenarios to calculate realistic emissions of greenhouse gases -- carbon dioxide and methane -, sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs) for atmospheric modeling programs that determine the associated amount of ozone. The team then employed a tool created by the Environmental Protection Agency to determine how the ozone in each scenario would affect the health of people in the region and also calculated the social costs of the associated greenhouse gas emissions.Their research predicts that in all scenarios, other than the one in which natural gas production becomes less costly, greenhouse gas emissions would be reduced following the closure of plants -- whether by planned retirement -- in the 2030 baseline scenario -- or as a cost-saving measure -- in the "expensive gas" and "greenhouse gas fees" scenarios.While this might not be a surprising finding at this point in our collective understanding of energy production and sustainability, the health and financial ripple effects of these changes are stark, according to the research."The reduction in ozone from 2011 to the 2030 baseline scenario is estimated to reduce total mortalities (sum of short-term and long-term mortalities) by about 200 annual deaths," according to the study.Metrics that associate an economic impact with mortality rate calculate that the health benefits of this scenario would equate to $2 billion.Mortality rates continue to improve under a scenario where fees are imposed on producers of greenhouse gas, along with an additional economic benefit of $200 million.Conversely, if gas prices were to fall -- resulting in greater use of it, and increased emissions -- the model predicts a spike in mortality rate that correlates to an $80 million reduction in the economic gains expected by 2030.The study highlights the difficult decisions facing policymakers when it comes to sourcing energy. For example, while shifting away from coal consumption toward natural gas and oil reduces carbon dioxide emissions, those benefits are offset by an increase in methane, sulfur dioxide and VOCs associated with the extraction and use of those sources.A policy that puts fees on greenhouse gas-emitting energy producers could be met with opposition, but it could also drive market forces toward greater use of energy from renewable sources like wind and solar, which are abundant in the region -- with the co-benefit of reducing emissions from gas and oil operations."This type of research continues to be important as other regions in the U.S. and abroad have access to similar technology for oil and gas extraction, as well as renewable energy production. The outcomes of this study ought to drive careful consideration of those choices," Capps said.In addition to Capps, this research was conducted by Rene Nzanzineza and Jana B. Milford from the University of Colorado at Boulder. It was supported by the National Science Foundation. | Ozone Holes | 2,019 |
July 23, 2019 | https://www.sciencedaily.com/releases/2019/07/190723121906.htm | Ozone threat from climate change | Increasing temperatures due to climate change will shift climatic conditions, resulting in worse air quality by increasing the number of days with high concentrations of ozone, according to a new journal article on air quality throughout the Mid-Atlantic region from researchers at the University of Delaware's College of Earth, Ocean and Environment(CEOE). | Cristina Archer led a team from CEOE as the members compiled nearly 50 years' worth of data from Delaware Department of Natural Resources and Environmental Control (DNREC) air monitoring and climate models to analyze climatic trends. They found that rising temperatures will increase the number of days in a year where ozone levels in Earth's lower atmosphere become dangerous.Archer said DNREC, which funded her study, is concerned with near-ground ozone levels for two main reasons: impacts on human health and compliance with federal and state regulations limiting high-ozone concentrations."Ozone has large negative impacts on health, especially affecting the cardiopulmonary and respiratory systems," Archer said. "It is especially bad if you already have a respiratory condition, asthma, for example, or an infection. In Delaware, we are barely in attainment or slightly in non-attainment (of ozone regulations). When we are not in attainment, the Environmental Protection Agency has to act. That is the relevance. That is why we need to know now there is a problem, so we can act on it."The study, titled "Global Warming Will Aggravate Ozone Pollution in the U.S. Mid-Atlantic," was recently published in the Archer is a professor in CEOE with a joint appointment between the Physical Ocean Science and Engineering (POSE) program of the School of Marine Science and Policy and the Department of Geography. Collaborators in the research and writing were Sara Rauscher, an associate professor in the Department of Geography, and Joseph Brodie, a former graduate student and postdoctoral researcher at CEOE who is currently director of atmospheric research at the Rutgers University Center for Ocean Observing Leadership.Ozone in the upper atmosphere is beneficial for blocking harmful ultraviolet (UV) rays from the sun. However, ozone closer to the surface of the Earth -- the focus of the study -- can lead to pulmonary complications among the population. Near-ground ozone can lead to coughing, irritation of the throat and chest, exacerbation of asthma, inflammation of lung cells, aggravation of chronic lung diseases, and ozone even reduces the disease-fighting capabilities of the immune system. On days where ozone levels are high enough, prolonged exposure can even lead to permanent lung damage. Ozone is regulated as a pollutant by the EPA because of ozone's hazardous nature.Near-ground ozone forms as a result of photochemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs). Intense UV rays from the sun are the catalyst for the reactions between NOx emissions and the VOCs. NOx emissions occur when cars or power plants burn fossil fuels such as coal and gasoline. VOCs are also human-made and derive from a variety of sources, including cars and gasoline-burning engines, paints, insecticides, cleaners, industrial solvents, and chemical manufacturing.According to Archer, limiting ozone is difficult because it is a secondary pollutant."There are primary pollutants that are emitted and there are secondary pollutants that form in the air," said Archer. "Ozone is one of these [secondary pollutants]. You can't go to a smokestack and measure the ozone coming out. You'll get precursors or other compounds that form it but never ozone itself."Most of the time, near-ground ozone is not an issue for Delaware. As outlined in Archer's paper, during the 1980s the average number of high-ozone days in Delaware was about 75, whereas by 2015 it was less than 20, decreasing by about two days every year due to stricter air quality regulations.However, the team of researchers found that increasing temperatures due to climate change are threatening to reverse the decrease in near-ground ozone pollution and increase the number of days where surface ozone levels become dangerous.Conditions that lead to high-ozone days are typical of hot summer days.As global temperatures increase, summers will continue to get hotter and will lead to more days with high ozone concentrations. Archer also stated that more high-ozone days could also occur during the fall and spring, since increasing global temperatures will make those seasons warmer on average. According to the Intergovernmental Panel for Climate Change, global temperatures have increased by one degree Celsius as of 2019 and will increase by another one degree Celsius by the end of the 21st century. Archer also said high-ozone days themselves may become more intense due to increased ozone concentrations.The increase in the number and intensity of high-ozone days is troubling because the adverse health effects impact anyone who spends ample time outdoors, including children and people who exercise outside. More people go outside more often during the summer, potentially increasing human exposure to dangerous levels of near-ground ozone.In the article, Archer said that a "business as usual" approach will inevitably lead to a dangerous increase in high-ozone days. Archer said that the country needs stricter regulations if it is to limit the number of high-ozone days. | Ozone Holes | 2,019 |
July 22, 2019 | https://www.sciencedaily.com/releases/2019/07/190722115931.htm | Airborne lidar system poised to improve accuracy of climate change models | Researchers have developed a laser-based system that can be used for airborne measurement of important atmospheric gases with unprecedented accuracy and resolution. The ability to collect this data will help scientists better understand how these atmospheric gases affect the climate and could help improve climate change predictions. | In the Optical Society journal The tropopause separates the surface-based troposphere layer where weather takes place from the overlying stratosphere that contains the ozone layer that protects life on Earth from harmful radiation. Scientists want to study water vapor and ozone in the tropopause because the distribution of these atmospheric gases in this layer plays a crucial role in the Earth's climate."The ability to detect the vertical structure of water vapor and ozone is critical for understanding the exchange of these atmospheric gases between the troposphere and the stratosphere," said Andreas Fix, who led the research team. "These measurements could help us identify errors and uncertainties in climate models that would help improve predictions of the future climate, which is one of the central challenges for our society and economy."Atmospheric gases can be assessed with instruments flown into the atmosphere or with data acquired from satellites. However, these methods haven't been able to provide a full picture of atmospheric gas distribution because they either lack the vertical component or don't provide high enough resolution. Although instruments carried with balloons -- known as balloon sondes -- can provide highly resolved vertical profiles they don't offer detailed temporal resolution and can only be used at selected sites.To solve these problems, the researchers developed a lidar system that uses laser light to measure both ozone and water vapor at the same time. Their approach, called differential absorption lidar (DIAL), uses two slightly different UV wavelengths to measure each gas. The UV radiation at one wavelength is mostly absorbed by the gas molecules while most of the other wavelength is reflected. Measuring the ratio of the UV signals returning from the atmosphere allows calculation of a detailed gas profile.The gas profiles created using the new lidar system exhibit a vertical resolution of around 250 meters and a horizontal resolution of about 10 kilometers below the aircraft's flight track."This vertical capability is a significant advancement in studying exchange processes at the tropopause," said Fix. "It helps overcome significant shortcomings in resolving the fine-scale distribution that have made it difficult to understand processes responsible for exchange at the tropopause."To perform this method aboard a plane, the researchers used a highly efficient optical parametric oscillator (OPO) they previously developed to convert the laser output to the UV wavelengths needed to measure water vapor and ozone. "The conversion needs to be very energy efficient to generate UV radiation with adequate pulse energies and high average power from the limited energy available on board an aircraft," explained Fix.Tests of the new lidar system showed that its accuracy matched well with that of balloon sondes. In 2017, the researchers flew the new system aboard the wave-driven isentropic exchange (WISE) mission, which involved multiple long-range flights over the North Atlantic and Northern Europe. They found that the instrument worked remarkably well, remained stable during use and could measure characteristic ozone and water vapor distributions at the tropopause.The researchers plan to analyze the new vertical-component data acquired during WISE and integrate it into climate models. They expect to use the instrument to collect data atmospheric gas information aboard future flights. | Ozone Holes | 2,019 |
July 16, 2019 | https://www.sciencedaily.com/releases/2019/07/190716151358.htm | By cutting ozone pollution now, China could save 330,000 lives by 2050 | If China takes strong measures to reduce its ozone pollution now, it could save hundreds of thousands of lives in the long run, according to a new study led by researchers at Columbia University's Lamont-Doherty Earth Observatory. | "Air pollution is a major problem in China right now," said lead author Daniel Westervelt, an associate research scientist at Lamont-Doherty. "It's a very serious health risk. So it's important to think about what changes can be made to make progress on this problem."High up in the atmosphere, the ozone layer protects our planet from harsh ultraviolet radiation. But when ozone gets into the air we breathe, it can lead to premature death from cardiovascular disease, stroke and respiratory problems. On-the-ground ozone pollution is created when other pollutants -- nitrogen oxides and volatile organic compounds -- react together with sunlight. Those pollutants can come from motor vehicles, power plants, factories and other human-made sources.Ozone pollution is already dangerously common in China, causing an estimated 67,000 premature deaths in 2015. But the new study, published today in The first scenario looked at what would happen if China's air pollution levels stay fixed but the climate continues to warm. The second scenario looked at the effects of climate change plus a 10 percent increase in ozone pollution emissions -- representing a 'status quo' strategy, according to Westervelt. And the third scenario analyzed the impacts of climate change plus an aggressive approach of cutting China's ozone-forming emissions by 60 percent.Plugging those scenarios into a model of atmospheric chemistry and climate, the team found that climate change alone could cause a 11 percent increase in ozone pollution in China. This would cause an additional 62,000 premature deaths by 2050.In the second scenario, a 10 percent increase in emissions of air pollutants combined with climate change caused an additional 80,000 premature deaths. On the other hand, a 60 percent decrease in ozone-forming emissions prevented 330,000 premature deaths.In all three simulations, climate change made ozone pollution worse than it would have been otherwise. That wasn't surprising; scientists know that warmer temperatures will speed up the reactions that create ozone and enhance conditions that allow it to accumulate near the surface. However, the study revealed another startling way that climate change could exacerbate ozone pollution: "It turns out that a major portion of the ozone increase we're seeing in the model in western China originates in the stratosphere," said Westervelt.It's normal for some ozone to trickle down from the ozone layer to the ground, but the model showed that by changing the jetstream and mixing patterns of the atmosphere, climate change could enhance the flow of ozone from the stratosphere to the surface, particularly over western China and the Tibetan plateau.The team also calculated that emissions from other countries, including India, could significantly detract from China's air quality gains if it does decide to reduce emissions. The authors write that China would benefit by encouraging emissions reductions throughout all of Asia. "If China is able to be a leader on this and say, 'We need to reduce our emissions,' other countries may follow suit," Westervelt suggested.The study shows that China is at an important crossroads, with its future air quality depending strongly on passing policies to reduce both ozone- and climate change-causing emissions, said Westervelt. "The issues of climate change and air quality go hand-in-hand, so it makes sense to tackle both things simultaneously."To be sure, cutting ozone-causing emissions by 60 percent wouldn't come easy. It would require many new policies to fall into place, such as increasing fuel efficiency standards, switching to electric vehicles, installing air pollution control devices on power plant smokestacks, and switching to cleaner sources of energy, such as natural gas and renewables. Nevertheless, the 60 percent reduction is feasible based on policy measures and technologies that already exist today, said Westervelt."I would hope that policymakers in China will take results like this and see that if you were to aggressively reduce emissions, you would reap the benefits in a pretty significant way," he said. "It's worth it to address these emissions now, so that you don't have to deal with all the health problems in the future. You could save 330,000 over the next few decades. That's a lot of lives."Other authors on the paper included: Arlene Fiore, Mike He, Marianthi-Anna Kioumourtzoglou, and Gustavo Correa from Columbia University; Clara Ma from Yale University; Patrick Kinney from Boston University; and Shuxiao Wang, Jia Xing, and Dian Ding of Tsinghua University. | Ozone Holes | 2,019 |
June 28, 2019 | https://www.sciencedaily.com/releases/2019/06/190628120533.htm | Pig-Pen effect: Mixing skin oil and ozone can produce a personal pollution cloud | When ozone and skin oils meet, the resulting reaction may help remove ozone from an indoor environment, but it can also produce a personal cloud of pollutants that affects indoor air quality, according to a team of researchers. | In a computer model of indoor environments, the researchers show that a range of volatile and semi-volatile gases and substances are produced when ozone, a form of oxygen that can be toxic, reacts with skin oils carried by soiled clothes, a reaction that some researchers have likened to the less-than-tidy Peanuts comic strip character."When the ozone is depleted through human skin, we become the generator of the primary products, which can cause sensory irritations," said Donghyun Rim, assistant professor of architectural engineering and an Institute for CyberScience associate, Penn State. "Some people call this higher concentration of pollutants around the human body the personal cloud, or we call it the 'Pig-Pen Effect.'"The substances that are produced by the reaction include organic compounds, such as carbonyls, that can irritate the skin and lungs, said Rim. People with asthma may be particularly vulnerable to ozone and ozone reaction products, he said.According to the researchers, who reported their findings in a recent issue of Nature's "Squalene can react very effectively with ozone," said Rim. "Squalene has a higher reaction rate with ozone because it has a double carbon bond and, because of its chemical makeup, the ozone wants to jump in and break this bond."Indoors, ozone concentration can range from 5 to 25 parts per billion -- ppb -- depending on how the air is circulating from outside to inside and what types of chemicals and surfaces are used in the building. In a polluted city, for example, the amount of ozone in indoor environments may be much higher."A lot of people think of the ozone layer when we talk about ozone," said Rim. "But, we're not talking about that ozone, that's good ozone. But ozone at the ground level has adverse health impacts."Wearing clean clothes might be a good idea for a lot of reasons, but it might not necessarily lead to reducing exposure to ozone, said Rim. For example, a single soiled t-shirt helps keep ozone out of the breathing zone by removing about 30 to 70 percent of the ozone circulating near a person."If you have clean clothes, that means you might be breathing in more of this ozone, which isn't good for you either," said Rim.Rim said that the research is one part of a larger project to better understand the indoor environment where people spend most of their time."The bottom line is that we, humans, spend more than 90 percent of our time in buildings, or indoor environments, but, as far as actual research goes, there are still a lot of unknowns about what's going on and what types of gases and particles we're exposed to in indoor environments," said Rim. "The things that we inhale, that we touch, that we interact with, many of those things are contributing to the chemical accumulations in our body and our health."Rather than advising people whether to wear clean or dirty clothes, the researchers suggest that people should focus on keeping ground ozone levels down. Better building design and filtration, along with cutting pollution, are ways that could cut the impact of the Pig-Pen Effect, they added.To build and validate the models, the researchers used experimental data from prior experiments investigating reactions between ozone and squalene, and between ozone and clothing. The researchers then analyzed further how the squalene-ozone reaction creates pollutants in various indoor conditions.The team relied on computer modeling to simulate indoor spaces that vary with ventilation conditions and how inhabitants of those spaces manage air quality, Rim said.In the future, the team may look at how other common indoor sources, such as candle and cigarette smoke, could affect the indoor air quality and its impact on human health. | Ozone Holes | 2,019 |
June 24, 2019 | https://www.sciencedaily.com/releases/2019/06/190624111536.htm | Damage to the ozone layer and climate change forming feedback loop | Increased solar radiation penetrating through the damaged ozone layer is interacting with the changing climate, and the consequences are rippling through the Earth's natural systems, effecting everything from weather to the health and abundance of sea mammals like seals and penguins. These findings were detailed in a review article published today in | "What we're seeing is that ozone changes have shifted temperature and precipitation patterns in the southern hemisphere, and that's altering where the algae in the ocean are, which is altering where the fish are, and where the walruses and seals are, so we're seeing many changes in the food web," said Kevin Rose, a researcher at Rensselaer Polytechnic Institute who serves on the panel and is a co-author of the review article.The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer -- the first multilateral environmental agreement to be ratified by all member nations of the United Nations -- was designed to protect Earth's main filter for solar ultraviolet radiation by phasing out production of harmful humanmade substances, such as the chlorofluorocarbons class of refrigerants. The treaty has largely been considered a success, with global mean total ozone projected to recover to pre-1980 levels by the middle of the 21st century. Earlier this year, however, researchers reported detecting new emissions of ozone depleting substances emanating from East Asia, which could threaten ozone recovery.While ozone depletion has long been known to increase harmful UV radiation at the Earth's surface, its effect on climate has only recently become evident. The report points to the Southern Hemisphere, where a hole in the ozone layer above Antarctica has pushed the Antarctic Oscillation -- the north-south movement of a wind belt that circles the Southern Hemisphere -- further south than it has been in roughly a thousand years. The movement of the Antarctic Oscillation is in turn directly contributing to climate change in the Southern Hemisphere.As climate zones have shifted southward, rainfall patterns, sea-surface temperatures, and ocean currents across large areas of the southern hemisphere have also shifted, impacting terrestrial and aquatic ecosystems. The effects can be seen in Australia, New Zealand, Antarctica, South America, Africa, and the Southern Ocean.In the oceans, for example, some areas have become cooler and more productive, where other areas have become warmer and less productive.Warmer oceans are linked to declines in Tasmanian kelp beds and Brazilian coral reefs, and the ecosystems that rely on them. Cooler waters have benefitted some populations of penguins, seabirds, and seals, who profit from greater populations of krill and fish. One study reported that female albatrosses may have become a kilogram heavier in certain areas because of the more productive cooler waters linked to ozone depletion.Rose also pointed to subtler feedback loops between climate and UV radiation described in the report. For example, higher concentrations of carbon dioxide have led to more acidic oceans, which reduces the thickness of calcified shells, rendering shellfish more vulnerable to UV radiation. Even humans, he said, are likely to wear lighter clothes in a warmer atmosphere, making themselves more susceptible to damaging UV rays.The report found that climate change may also be affecting the ozone layer and how quickly the ozone layer is recovering."Greenhouse gas emissions trap more heat in the lower atmosphere which leads to a cooling of the upper atmosphere. Those colder temperatures in the upper atmosphere are slowing the recovery of the ozone layer," Rose said.As one of three scientific panels to support the Montreal Protocol, the Environmental Effects Assessment Panel focused in particular on the effects of UV radiation, climate change, and ozone depletion. Thirty-nine researchers contributed to the article, which is titled "Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future." Rose, an aquatic ecologist, serves on the aquatic ecosystems working group, which is one of seven working groups that are part of the panel."This international collaboration focusing on a pressing problem of global significance exemplifies the research vision of The New Polytechnic at Rensselaer," said Curt Breneman, dean of the Rensselaer School of Science." | Ozone Holes | 2,019 |
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