Paper: Increasing co-occurrence of fine particulate matter and ground-level ozone extremes in the western United States — Science Advances

Smoke from the East Troublesome fire looms over Granby Reservoir. Photo credit: Evan Wise via Water for Colorado

Click here to access the paper (Dmitri a. Kalashnikov Jordan l. Schnell John t. Abatzoglou Daniel l. Swain and Deepti Singh). Here’s the abstract:

Wildfires and meteorological conditions influence the co-occurrence of multiple harmful air pollutants including fine particulate matter (PM2.5) and ground-level ozone. We examine the spatiotemporal characteristics of PM2.5/ozone co-occurrences and associated population exposure in the western United States (US). The frequency, spatial extent, and temporal persistence of extreme PM2.5/ozone co-occurrences have increased significantly between 2001 and 2020, increasing annual population exposure to multiple harmful air pollutants by ~25 million person-days/year. Using a clustering methodology to characterize daily weather patterns, we identify significant increases in atmospheric ridging patterns conducive to widespread PM2.5/ozone co-occurrences and population exposure. We further link the spatial extent of co-occurrence to the extent of extreme heat and wildfires. Our results suggest an increasing potential for co-occurring air pollution episodes in the western US with continued climate change.

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