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At left, Juan Delgado, Norse Peak Fires public information officer, and another firefighter watch the Norse Peak Fire burn on Wednesday, August 30, 2017. (JAKE PARRISH/Yakima Herald-Republic file)

After a 2017 summer in which residents across the West, including those in the Yakima Valley, endured smoke from wildfires, a group of scientists have presented new information suggesting that air pollution from such massive blazes may be one of their deadliest consequences.

Researchers from Colorado State University and the University of Houston recently suggested that wildfires may be responsible for thousands of U.S. deaths annually due to the tiny pollution particles they put into the atmosphere.

Moreover, just as fires are expected to worsen under climate warming, so might these health impacts.

“If this is the new norm for California ... and people in California are being exposed to these smoke events regularly, then we would expect this to have an impact on the average lifetime of people in California,” said Jeffrey Pierce, a professor of atmospheric science at Colorado State University who presented his preliminary results at the annual American Geophysical Union meeting in New Orleans earlier this month.

Just like smokestacks and tailpipes, wildfires fill the air with the byproducts of combustion, including very dangerous small particles known as PM2.5, which can get into the lungs and bloodstream. A growing body of research has demonstrated that these particles degrade health and contribute to thousands of deaths each year in the U.S. alone by causing respiratory, cardiovascular and other health problems.

So just how deadly is the smoke from wildfires? While the numbers presented are definitely preliminary, they suggest the cost could be severe indeed.

Pierce presented the highest numbers at the meeting. He estimates that 5,000 to 25,000 people in the U.S. may die each year from PM2.5 that specifically comes from the smoke of wildfires burning in the U.S. and nearby countries such as Canada.

But the number of wildfire-linked deaths could triple by the end of the century for high levels of global warming, Pierce has found, based on one climate modeling scenario (which, Pierce emphasizes, is only a preliminary finding and should be replicated by other scientific groups).

That would lead to a situation in which, as other sources of air pollution decline, wildfires become an increasingly dominant overall source of PM2.5.

“Coal plants have gotten cleaner, wildfires have slightly increased over the past decades, so, wildfires are on the verge of becoming, if they haven’t become, the largest source of particulate matter in the U.S.,” Pierce said in an interview.

Dr. Sara Cate, of Yakima, said she expects the fire seasons of the next 10 years to resemble last summer’s in terms of number and strength of wildfires. While that will likely have a health effect on all people, Cate said it will disproportionately hurt poorer populations that can’t afford to adapt to the increasing amount of toxins.

“Yeah, it will help to have ways to clean our air inside and change filters,” said Cate, a family medicine practitioner who has researched climate change extensively and lectured on the topic. “But we live in Yakima. It’s one of the poorest communities in the state and a lot of people don’t have the resources. They have the diseases but they don’t have the resources to adapt to these changes.”

People most at risk have already-existing lung or heart problems or are elderly or children, said Pacific Northwest University pediatric department chair Melissa Lemp.

“The smoke narrows the airways of the lungs that then obstructs breathing and can cause secondary infection, which is the cause of death,” Lemp said. “It kind of affects the mechanics of the lungs and slows the movement of oxygen.”

Pierce’s results, not yet published formally, are similar to those of Ebrahim Eslami, a Ph.D. student at the University of Houston who also presented at the meeting on wildfire-related air pollution deaths. He has found that wildfires and other burning of biomass, such as in the agricultural sector, contribute to about 5,000 deaths per year. That equates to annual economic damages of $40 billion to $50 billion for the period from 2011 to 2014.

“Billions of dollars, or tens of billions of dollars, that’s the magnitude of the cost caused by wildfires due to health impact incidence,” Eslami said.

The studies include not only the effects of raging wildfires, but also controlled burns, in which forest managers deliberately light fires to burn away some of the fuel and reduce the danger of more dangerous outbreaks later. The health effects are of course not evenly distributed — they are the worst in areas closest to large wildfires, such as California, the Pacific Northwest and the Southeast.

While Pierce’s and Eslami’s results are not yet formally published, they don’t sound so different from a just-published result from a group of scientists with the Environmental Protection Agency and several Australian institutions. These researchers found that “short term” premature deaths tied to wildfire air pollution in the U.S. from 2008 to 2012 numbered from 1,500 to 2,500 each year. They calculated that the economic toll, meanwhile, was tens of billions each year.

And these were only short-term effects. Over the longer term, the researchers calculated even more severe numbers.

Other recently published work has found that the air pollution contributed by wildfires has been greatly underestimated and that in the western U.S. during wildfire seasons from 2004 to 2009, fires contributed 12 percent of the total PM2.5 concentrations in the atmosphere, and far more than that on days with particularly poor air quality. The research projected that this situation would get considerably worse due to climate change.

Many health outcomes less severe than death also are triggered by wildfire smoke, particularly in the immediate vicinity of fires, such as asthma attacks and hospital trips for a variety of conditions.

“A severe short-term smoke event increases the number of (asthma) inhaler refills by an order of magnitude,” said Katelyn O’Dell, a researcher at Colorado State who is working with Pierce studying the health effects of wildfires.

This past summer, Cate treated an elevated number of adults who are smokers or who have COPD or other breathing problems.

“They were having worsening shortness of breath and needing more antibiotics,” said Cate, who commutes to her job at an Ellensburg practice. “What you see with the poor air quality is an increase in frequency of exacerbations of the underlying illness.”

Granted, Pierce’s and Eslami’s findings should be taken cautiously, because this research is fairly new.

Soon adding to that pool of research will be a Washington state Department of Ecology study looking specifically at the death and health impacts from summer 2017 wildfires.

Moreover, researchers acknowledge that wildfire smoke differs in complex ways from other types of air pollution — and indeed, depends on where wildfires occur, and what they consume.

“What burns matters,” said Manvendra Dubey, a researcher at Los Alamos National Laboratory, who also is working on the problem of wildfire smoke and its consequences.

Yakima Herald-Republic reporter Kaitlin Bain contributed to this story.