Researchers report a link between airborne fine particulate matter and wildfire activity in the United States. Fine particulate matter smaller than 2.5 μm in diameter (PM2.5) has significant adverse effects on pulmonary and cardiovascular health. Wildfires are a major source of PM2.5, and the frequency and duration of large wildfires in the northwestern United States has been increasing since the mid-1980s. Crystal McClure and Daniel Jaffe evaluated trends in PM2.5 across the contiguous United States for 1988-2016 based on data from rural monitoring sites. The authors found that the 98th quantile of annual PM2.5 has been increasing in much of the Northwest, including all or parts of Montana, Idaho, Oregon, California, Nevada, Utah, and Wyoming. By contrast, 98th quantile PM2.5 has been decreasing in most of the rest of the United States. Trends in total carbon, a marker for wildfire emissions, paralleled those for 98th quantile PM2.5, with increasing total carbon in the Northwest and decreasing total carbon in the rest of the United States. According to the authors, the results suggest that increased wildfire activity is associated with increased extreme PM2.5 levels in the Northwest, potentially offsetting reductions in anthropogenic PM2.5.
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Article #18-04353: "US particulate matter air quality improves except in wildfire-prone areas," by Crystal D. McClure and Daniel A. Jaffe.
MEDIA CONTACT: Daniel A. Jaffe, University of Washington, Seattle, WA; tel: 425-352-5357; e-mail: djaffe@uw.edu
Proceedings of the National Academy of Sciences