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LANL scientist studying effects of wildfire smoke

Smoke rises from the Medio Fire in the Sangre de Cristo Mountains north of Santa Fe that burned 4,000 acres in the Santa Fe National Forest in August this year. (Eddie Moore/Albuquerque Journal)

Copyright © 2020 Albuquerque Journal

It is not too surprising that nearby major forest fires – such as this summer’s Rio Medio Fire – spew particulates into the air that can affect health.

But even fires 1,000 miles away can also have detrimental health effects.

It is something that Manvendra Dubey, a Los Alamos National Laboratory Fellow, is starting to study full-time, since just how serious those health problems can be is still not completely clear.

A native of India who earned his doctorate at Harvard while studying stratospheric ozone depletion, Dubey has been in Los Alamos 24 years so he lived there through both of the catastrophic fires that afflicted the area – the Cerro Grande Fire in 2000 and the Las Conchas Fire in 2011.

Coupled with the major fires that have ravaged the Pacific Coast the past few years, Dubey has turned his attention to aerosol gas forensic experiments, “studying the nexus of climate change, energy security and national security,” he said.

As they consume trees and undergrowth, fires have immediate consequences for people living nearby, Dubey said, especially those already afflicted with such breathing problems as asthma.

Smoke from the Medio Fire in the Sangre de Cristo Mountains north of Santa Fe blends in with clouds on the horizon. (Eddie Moore/Albuquerque Journal)

“Smoke is a problem, the aerosols, including biomass burning,” he said. “One of the questions is how dark is the smoke. If it’s white, what does that mean? It’s complicated.”

When it is primarily black, smoke has high concentrates of larger-particulated soot that can contain such minerals as iron or mercury, as well as gases such as carbon dioxide, he said.

“They also produce smaller amounts of gases like CO (carbon monoxide) and even smaller amount of organics like formaldehyde and methanol,” Dubey said. “Generally, early in a wildfire, the forest burns fast and quick – this flaming phase produces large amounts of dark soot (20%) (that) can be seen as dark rising plumes that are lofted high and amenable to long-range transport.”

As smoke travels, it becomes less concentrated as it mixes with ambient air. But, at the same time, the composition changes, as well,” he said.

“Generally, because the smoke travels through the sunlight atmosphere, photochemistry takes place,” Dubey said. “It oxidizes everything in the fumes and they become more reactive. The aged smoke actually can be more reactive and potentially more impactful in your lungs. It’s more excited and more active, as the chemistry suggests. There’s a tradeoff between concentration and content.”

It is for this reason, particularly with fire season seeming to get worse every year, he said, that additional study is crucial.

For instance, this summer, Washington, D.C., recorded its highest levels of black carbon, which can be directly attributable to the fires on the West Coast.

That actually caused more people to seek medical attention, which meant they were also getting tested for COVID-19 and the number of COVID-19 detections went up, Dubey said.

“Smoke exposure can exacerbate other things, like asthma and influenza,” he said.

As the fire is attacked and reduced from its high temperatures and quick burning to more surface smoldering, smoke conditions change again.

Manvendra Dubey

“Later, as the fire is controlled, the lower temperature results in smoldering, less-hot fires that emit white organic-rich smoke,” Dubey said. “At these temperatures, more organic compounds are emitted and the toxicity of smoke is higher. The smoke also smolders at night as temperatures are cooler and also as the boundary layer is capped; it results in accumulation and increased exposure to nearby communities.”

Just in the time since the two Los Alamos fires, equipment for measuring and studying the fallout has increased significantly, he said, and as additional focus is brought to bear on the issue, that should improve even more dramatically.

“We use research-grade instruments, such as spectrometers that use lasers to mimic sunlight to measure their particle size and optical properties, as well as the composition of the gases like (carbon monoxide), formaldehyde, (carbon dioxide), methane, ethane and dinitrogen monoxide,” Dubey said. “We also measure soot using a laser-induced incandescence – the black soot absorbs the laser heat and glows. We also use an aerosol mass spectrometer to measure the composition of the smoke, including metals that can be a health hazard.”

Long-term health concerns are of particular issue and are gaining more attention among scientists, especially in Los Alamos, he said. Among the many potential ramifications, cancer is a major concern.

Likewise, Dubey added, determining the detriment to the environment needs to be examined.

“We also have a solid research program on climate,” Dubey said. “And smoke from wildfires is a key feedback that is hard to predict (in terms of) its impact on longer-term climate.”

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