LANLSAYS WILDFIRES MAY CONTRIBUTE MORE TO GLOBAL WARMING THAN HAD BEEN THOUGHT

FROM:  LOS ALAMOS NATIONAL LABORATORY
Wildfires May Contribute More To Global Warming Than Previously Predicted

Particle analysis shows “tar ball” effect is significant

LOS ALAMOS, N.M., July 9, 2013—Wildfires produce a witch’s brew of carbon-containing particles, as anyone downwind of a forest fire can attest. A range of fine carbonaceous particles rising high into the air significantly degrade air quality, damaging human and wildlife health, and interacting with sunlight to affect climate. But measurements taken during the 2011 Las Conchas fire near Los Alamos National Laboratory show that the actual carbon-containing particles emitted by fires are very different than those used in current computer models, providing the potential for inaccuracy in current climate-modeling results.

“We’ve found that substances resembling tar balls dominate, and even the soot is coated by organics that focus sunlight,” said senior laboratory scientist Manvedra Dubey, “Both components can potentially increase climate warming by increased light absorption.”

The Las Conchas fire emissions findings underscore the need to provide a framework to include realistic representation of carbonaceous aerosols in climate model, the researchers say. They suggest that fire emissions could contribute a lot more to the observed climate warming than current estimates show.

“The fact that we are experiencing more fires and that climate change may increase fire frequency underscores the need to include these specialized particles in the computer models, and our results show how this can be done,” Dubey said.

Aerosol samples revealed “tar balls” in the skies

Conventional wisdom is that the fire-driven particles contain black carbon or soot that absorbs sunlight to warm the climate, and organic carbon or smoke that reflects sunlight to cool the climate. But in a paper just published in Nature Communications the scientists from Los Alamos and Michigan Technological University analyzed the morphology and composition of the specific aerosols emitted by the Las Conchas fire.

Las Conchas, which started June 26, 2011, was the largest fire in NM history at the time, burning 245 square miles. Immediately after Los Alamos National Laboratory reopened to scientists and staff, the team set up an extensive aerosol sampling system to monitor the smoke from the smoldering fire for more than 10 days.

High-tech tools enable analysis of smoke samples

Dubey, along with postdoctoral fellow Allison Aiken and post-bachelor’s student Kyle Gorkowski, coordinated with Michigan Tech professor Claudio Mazzoleni (a former Los Alamos Director’s fellow) and graduate student Swarup China to perform this study.

The team used field-emission scanning electron microscopy and energy dispersive X ray spectroscopy to analyze the aerosol samples and determined that spherical carbonaceous particles called tar balls were 10 times more abundant than soot.

Furthermore, the bare soot particles, which are composite porous fractal structures made of tiny spherical carbon, are modified significantly by the organics emitted by the fire. About 96 percent of the soot from the fire is coated by other organics substances, with 50 percent being totally coated. Furthermore, the complexity of the soot can be categorized into 4 morphological structures as “embedded,” “partly coated,” “with inclusions” and “bare.”

What was missing from the modeling and why it matters

Why is this important for climate? Dubey noted that, “Most climate assessment models treat fire emissions as a mixture of pure soot and organic carbon aerosols that offset the respective warming and cooling effects of one another on climate. However Las Conchas results show that tar balls exceed soot by a factor of 10 and the soot gets coated by organics in fire emissions, each resulting in more of a warming effect than is currently assumed.”

“Tar balls can absorb sunlight at shorter blue and ultraviolet wavelengths (also called brown carbon due to the color) and can cause substantial warming,” he said. “Furthermore, organic coatings on soot act like lenses that focus sunlight, amplifying the absorption and warming by soot by a factor of 2 or more. This has a huge impact on how they should be treated in computer models.”

This experimental research was funded by the U.S. Department of Energy’s Office of Science.

EPA ANNOUCES UPDATE ON FINE PARTICLE POLLUTION

FROM: U.S. ENVIRONMENTAL PROTECTION AGENCY

EPA Announces Next Round of Clean Air Standards to Reduce Harmful Soot Pollution 
WASHINGTON – In response to a court order, the U.S. Environmental Protection Agency (EPA) today finalized an update to its national air quality standards for harmful fine particle pollution (PM2.5), including soot, setting the annual health standard at 12 micrograms per cubic meter. By 2020, ninety-nine percent of U.S. counties are projected to meet revised health standard without any additional actions

Today’s announcement has no effect on the existing daily standard for fine particles or the existing daily standard for coarse particles (PM10), which includes dust from farms and other sources), both of which remain unchanged.

"These standards are fulfilling the promise of the Clean Air Act. We will save lives and reduce the burden of illness in our communities, and families across the country will benefit from the simple fact of being able to breathe cleaner air," said EPA Administrator Lisa P. Jackson.

Fine particle pollution can penetrate deep into the lungs and has been linked to a wide range of serious health effects, including premature death, heart attacks, and strokes, as well as acute bronchitis and aggravated asthma among children. A federal court ruling required EPA to update the standard based on best available science. Today’s announcement, which meets that requirement, builds on smart steps already taken by EPA to slash dangerous pollution in communities across the country. Thanks to these steps, 99 percent of U.S. counties are projected to meet the standard without any additional action.

It is expected that fewer than 10 counties, out of the more than 3,000 counties in the United States, will need to consider any local actions to reduce fine particle pollution in order to meet the new standard by 2020, as required by the Clean Air Act. The rest can rely on air quality improvements from federal rules already on the books to meet this new standard.

The standard, which was proposed in June and is consistent with the advice from the agency’s independent science advisors, is based on an extensive body of scientific evidence that includes thousands of studies – including many large studies which show negative health impacts at lower levels than previously understood. It also follows extensive consultation with stakeholders, including the public, health organizations, and industry, and after considering more than 230,000 public comments.

By 2030, it is expected that all standards that cut PM2.5 from diesel vehicles and equipment alone will prevent up to 40,000 premature deaths, 32,000 hospital admissions and 4.7 million days of work lost due to illness.

Because reductions in fine particle pollution have direct health benefits including decreased mortality rates, fewer incidents of heart attacks, strokes, and childhood asthma, the PM2.5 standards announced today have major economic benefits with comparatively low costs. EPA estimates health benefits of the revised standard to range from $4 billion to over $9 billion per year, with estimated costs of implementation ranging from $53 million to $350 million. While EPA cannot consider costs in selecting a standard under the Clean Air Act, those costs are estimated as part of the careful analysis undertaken for all significant regulations, as required by Executive Order 13563 issued by President Obama in January 2011.

The Clean Air Act requires EPA to review its air quality standards every five years to determine whether the standards should be revised. The law requires the agency to ensure the standards are "requisite to protect public health with an adequate margin of safety" and "requisite to protect the public welfare." A federal court required EPA to issue final standard by December 14, because the agency did not meet its five-year legal deadline for reviewing the standards.

EPA carefully considered extensive public input as it determined the appropriate final standard to protect public health. The agency held two public hearings and received more than 230,000 written comments before finalizing today’s updated air quality standards.