Document


Title

Contribution of wildland-fire smoke to US PM2.5 and its influence on recent trends
Document Type: Journal
Author(s): Katelyn O'Dell ; Bonne Ford Hotmann ; Emily V. Fischer ; Jeffrey R. Pierce
Publication Year: 2019

Cataloging Information

Keyword(s):
  • area burned
  • fire frequency
  • GEOS-Chem
  • GEOS-Chem CTM
  • PM - particulate matter
  • PM2.5
  • smoke plumes
Record Maintained By:
FRAMES Staff; catalog@frames.gov
Record Last Modified: April 11, 2019
FRAMES Record Number: 57663

Description

Seasonal-mean concentrations of particulate matter with diameters smaller than 2.5 μm (PM2.5) have been decreasing across the United States (US) for several decades, with large reductions in spring and summer in the eastern US. In contrast, summertime-mean PM2.5 in the western US has not significantly decreased. Wildfires, a large source of summertime PM2.5 in the western US, have been increasing in frequency and burned area in recent decades. Increases in extreme PM2.5 events attributable to wildland fires have been observed in wildfire-prone regions, but it is unclear how these increases impact trends in seasonal-mean PM2.5. Using two distinct methods, (1) interpolated surface observations combined with satellite-based smoke plume estimates and (2) the GEOS-Chem chemical transport model (CTM), we identify recent trends (2006-2016) in summer smoke, nonsmoke, and total PM2.5 across the US. We observe significant decreases in nonsmoke influenced PM2.5 in the western US and find increases in summer-mean smoke PM2.5 in fire-prone regions, although these are not statistically significant due to large interannual variability in the abundance of smoke. These results indicate that without the influence of wildland fires, we would expect to have observed improvements in summer fine particle pollution in the western US but likely weaker improvements than those observed in the eastern US.

Online Link(s):
Citation:
O’Dell, Katelyn; Ford, Bonne; Fischer, Emily V.; Pierce, Jeffrey R. 2019. Contribution of wildland-fire smoke to US PM2.5 and its influence on recent trends. Environmental Science and Technology 53(4):1797-1804.