Smoke from unprecedented wildfires has rolled back decades of air quality gains, causing thousands of premature deaths in the past 20 years, according to a new study.
The Clean Air Act of 1963 aimed to lower air pollution by regulating emissions, and for decades, air quality in the U.S. steadily improved. Despite those efforts, air quality deteriorated between 2000 and 2020 due to wildfires, a study published Monday in The Lancet Planetary Health found. This caused 670 premature deaths annually in the 20-year period.
“Our air is supposed to be cleaner and cleaner due mostly to EPA regulations on emissions, but the fires have limited or erased these air-quality gains,” co-first author Jun Wang, chair of the University of Iowa’s Department of Chemical and Biochemical Engineering, said in a statement. “In other words, all the efforts for the past 20 years by the EPA to make our air cleaner basically have been lost in fire-prone areas and downwind regions. We are losing ground.”
Wildfires and Air Quality
Researchers came to this conclusion by calculating the concentration of fine particulate matter (PM 2.5) and a “highly toxic” element of air pollutant known as “black carbon.” They found that nationwide, PM 2.5 and black carbon decreased by 22 percent and 11 percent, respectively, between 2000 and 2020.
However, the western United States has seen a 55-percent annual increase in PM 2.5 and an 86 percent increase in black carbon since 2010. The Midwest has also been affected, but has escaped direct health effects. The eastern U.S. saw no significant air quality declines.
The study did not account for wildfires that have occurred since 2020, including the 2023 wildfires that swept across Canada over the summer, leading to the worst air quality parts of the U.S. had seen in recorded history. It is the second study to confirm deteriorating air quality due to wildfires in the past 20 years.
“We are on the borderline,” Wang continued. “If fires increase or become more frequent, our air quality will get worse.”
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