SAN DIEGO, California, October 24, 2008 (ENS) – A gas used in manufacture of flat panel televisions, computer displays, microcircuits, and thin-film solar panels is 17,000 times more potent a greenhouse gas than carbon dioxide, and it is far more prevalent in the atmosphere than previously estimated.

The powerful greenhouse gas nitrogen trifluoride, NF3, is at least four times more widespread than scientists had believed, according to new research by a team at Scripps Institution of Oceanography at the University of California, San Diego.

Using new analytical techniques, a team led by Scripps geochemistry professor Ray Weiss made the first atmospheric measurements of nitrogen trifluoride, NF3.

“Accurately measuring small amounts of NF3 in air has proven to be a very difficult experimental problem, and we are very pleased to have succeeded in this effort,” Weiss said Thursday, announcing the results of his team’s research.

The research findings will be published October 31 in “Geophysical Research Letters,” a journal of the American Geophysical Union.

Scripps geoscientists Ray Weiss, left, and Jens
Muehle show cylinders used to collect air
samples that they analyzed for
concentrations of nitrogen trifluoride.
(Photo courtesy Scripps Institution of
Oceanography, UC San Diego)

The amount of the gas in the atmosphere, which could not be detected using previous techniques, had been estimated at less than 1,200 metric tons in 2006. The new research shows the actual amount was 4,200 metric tons.

In 2008, about 5,400 metric tons of the gas was in the atmosphere, a quantity that is increasing at about 11 percent per year.

This rate of increase means that about 16 percent of the amount of the gas produced globally is being emitted into the atmosphere, the researchers estimate.

Emissions of NF3 were thought to be so low that the gas was not considered to be a significant potential contributor to global warming.

Nitrogen trifluoride was not covered by the Kyoto Protocol, the 1997 agreement to reduce greenhouse gas emissions signed by 182 countries, although three other fluoride compounds are covered.

The protocol governs the emissions of carbon dioxide, methane, and nitrous oxide as well as other fluoride compounds – sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons.

In response to the growing use of the gas and concerns that its emissions are not well known, the scientists have recommended adding it to the list of greenhouse gases regulated by the protocol or its successor agreement now under negotiation.

“From a climate perspective, there is a need to add NF3 to the suite of greenhouse gases whose production is inventoried and whose emissions are regulated under the Kyoto Protocol, thus providing meaningful incentives for its wise use,” said Weiss.

Nitrogen trifluoride is one of several gases used during the manufacture of liquid crystal flat-panel displays, thin-film photovoltaic cells and microcircuits.

Many industries have used the gas in recent years as an alternative to perfluorocarbons, which are also potent greenhouse gases, because it was believed that no more than two percent of the NF3 used in these processes escaped into the atmosphere.

To obtain their information, the Scripps team analyzed air samples gathered in California and Tasmania over the past 30 years by the NASA-funded Advanced Global Atmospheric Gases Experiment network of ground-based stations.

The network was created in the 1970s in response to international concerns about chemicals depleting the ozone layer. It is supported by NASA as part of its congressional mandate to monitor ozone-depleting trace gases, many of which are also greenhouse gases.

The researchers found concentrations of NF3 rose from about 0.02 parts per trillion in 1978 to 0.454 parts per trillion in 2008.

Higher concentrations of NF3 were found in the Northern Hemisphere than in the Southern Hemisphere, which the researchers said is consistent with its greater use in Northern Hemisphere countries.

“This result reinforces the critical importance of basic research in determining the overall impact of the information technology industry on global climate change, which has already been estimated to be equal to that of the aviation industry,” said Larry Smarr, director of the California Institute for Telecommunications at University of California, San Diego, who was not involved in the Scripps study.

Michael Prather is a University of California, Irvine atmospheric chemist who predicted earlier this year that based on the rapidly increasing use of NF3, larger amounts of the gas would be found in the atmosphere. Prather said the new Scripps study provides the confirmation needed to establish reporting requirements for production and use of the gas.

“I’d say case closed. It is now shown to be an important greenhouse gas,” said Prather, who was not involved with the Scripps study. “Now we need to get hard numbers on how much is flowing through the system, from production to disposal.”

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BOULDER, Colorado, October 9, 2008 (ENS) – Wildfires can hike ozone pollution to levels that violate U.S. public health and environmental standards, new research has determined.

The study by scientists at the National Center for Atmospheric Research focused on California wildfires in 2007, finding that they repeatedly caused ground-level ozone to spike to unhealthy levels across a broad area, including much of rural California as well as neighboring Nevada.

Fires worsen ozone levels by releasing nitrogen oxides and hydrocarbons, which can form ozone near the fire or far downwind as a result of chemical reactions in sunlight.

The study was published today in “Geophysical Research Letters.” It was funded by NASA and by the National Science Foundation, which sponsors NCAR.

Blaze at night on the Panther Fire
in north central California, August 6,
2008. (Photo by Art Gonzales)

“It’s important to understand the health impacts of wildfires,” says NCAR scientist Gabriele Pfister, the lead author. “Ozone can hit unhealthy levels even in places where people don’t see smoke.”

Although scientists have long known that wildfires can affect air quality by emitting particles and gases into the air, there has been little research to quantify the impacts.

The researchers, using a combination of computer models and ground-level measurements, studied intense California wildfires that broke out in September and October of 2007. They found that ozone was three times more likely to violate safe levels when fire plumes blew into a region than when no plumes were present.

At the time of the wildfires, the public health standard for ozone set by the U.S. Environmental Protection Agency was 0.08 parts per million over an eight-hour period.

The EPA has since tightened the standard to 0.075 parts per million. Under the stricter standard, the number of violations would have nearly doubled.

While ozone in the stratosphere benefits life on Earth by blocking ultraviolet radiation from the Sun, ozone in the lower atmosphere can trigger health problems.

These range from coughing and throat irritation to more serious problems, such as aggravation of asthma, bronchitis, and emphysema. Ground-level ozone pollution also damages crops and other plants.

“Wildfires are expected to worsen in the future, especially as our climate grows warmer,” Pfister says. “But we are only now beginning to understand their potential impacts on people and ecosystems, not only nearby but also potentially far downwind.”

The unhealthy levels of ozone the researchers detected occurred mostly in rural areas. This finding may be a result of the computer modeling, which lacked the fine detail to zoom in on relatively compact urban areas.

But the authors also speculate that wildfire emissions have a greater impact on ozone levels in the countryside than on cities.

They say cities tend to have more nitrogen dioxide, a pollutant that can, at high levels, reduce the efficiency with which ozone is produced or even destroy ozone.

“The impact of wildfires on ozone in suburban and rural areas, far from urban sources of pollution, was quite noticeable,” says NCAR scientist Christine Wiedinmyer, a co-author of the paper.

The paper notes that ozone levels would likely have been even greater except that Santa Ana winds in October blew wildfire plumes over the Pacific Ocean, safely away from populated areas.

To measure the impact of the fires on ozone formation, the researchers used a pair of computer models developed at the National Center for Atmospheric Research.

With the first one, a specialized fire model, they estimated the amount of vegetation burned and resulting emissions of nitrous oxides, sulfur dioxide, and other pollutants.

Those results went into a global air chemistry model that simulated the movement of the emissions and tracked the resulting formation of ozone as the fire plumes spread downwind.

The scientists verified the accuracy of their modeling results by comparing them with ozone measurements from a network of EPA ground stations at various sites in California.

This also allowed them to determine both the number of ozone violations and the extent to which the wildfires contributed to those violations.

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STANFORD, California, January 3, 2007 (ENS) – For each increase of one degree Celsius in the global temperature caused by carbon dioxide emissions, the resulting air pollution would lead annually to about 1,000 additional deaths and many more cases of respiratory illness and asthma across the United States, finds new Stanford University research released today.

Worldwide, upward of 20,000 air pollution related deaths per year per degree Celsius may be due to heat-trapping carbon dioxide emissions, according to the paper by Mark Jacobson, a professor of civil and environmental engineering at Stanford.

The research is the first to track the health effects of carbon dioxide emissions. It documents the direct links between increased levels of carbon dioxide in the atmosphere and increases in human mortality.

For Californians the effect is even greater. Jacobson’s paper offers concrete evidence that California is facing a particularly difficult situation if carbon dioxide emissions increase.

Air pollution in Los Angeles,
California (Photo courtesy U.S. EPA)

The study finds that the effects of carbon dioxide’s warming are greatest where pollution is already severe. Given that California has six of the 10 U.S. cities with the worst air quality, the state is likely to bear an increasingly disproportionate burden of death if no new restrictions are placed on carbon dioxide emissions.

The new findings, to be published in the journal “Geophysical Research Letters,” come to light just after the U.S. Environmental Protection Agency’s ruling against states setting their own emission standards for this greenhouse gas based in part on the lack of data showing the link between carbon dioxide emissions and their health effects.

On December 19, 2007, the EPA denied California and 16 other states a waiver that would have allowed the states to set their own emission standards for carbon dioxide, which is not currently regulated. The EPA denied the waiver partly on the grounds that no special circumstances existed to warrant an exception for the states.

Stephen Johnson, the EPA administrator, said California’s petition for a waiver of federal standards was denied because the state had failed to prove the “extraordinary and compelling conditions” required to qualify for a waiver.

“With six of the 10 most polluted cities in the nation being in California, that alone creates a special circumstance for the state,” Jacobson said.

Increased warming due to carbon dioxide will worsen people’s health in those cities at a much faster clip than elsewhere in the nation, he said.

Jacobson said more than 30 percent of the 1,000 excess deaths due to each degree Celsius increase caused by carbon dioxide occurred in California, which has a population of about 12 percent of the United States.

This indicates a much higher effect of carbon dioxide-induced warming on California health than that of the nation as a whole.

“This is a cause and effect relationship, not just a correlation,” said Jacobson. “The study is the first specifically to isolate carbon dioxide’s effect from that of other global-warming agents and to find quantitatively that chemical and meteorological changes due to carbon dioxide itself increase mortality due to increased ozone, particles and carcinogens in the air.”

Jacobson used a computer model to determine the amounts of ozone and airborne particles that result from temperature increases, caused by increases in carbon dioxide emissions.

He observed that higher temperatures due to carbon dioxide increased the chemical rate of ozone production in urban areas. And he noticed that increased water vapor due to carbon dioxide-induced higher temperatures boosted chemical ozone production even more in urban areas.

“Ultimately, you inhale a greater abundance of deleterious chemicals due to carbon dioxide and the climate change associated with it, and the link appears quite solid,” he said. “The logical next step is to reduce carbon dioxide: That would reduce its warming effect and improve the health of people in the U.S. and around the world who are currently suffering from air pollution health problems associated with it.”

Jacobson added that much of the population of the United States already has been directly affected by climate change through the air they have inhaled over the last few decades and that the health effects would grow worse if temperatures continue to rise.

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