Spatiotemporal Association of Coronavirus Disease 2019 Cases and Deaths With Exposure to Wildfire Particulate Matter in 2020

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Wildfires in California during 2020 were linked to increased COVID-19 cases and mortality rates due to exposure to particulate matter from smoke.
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The study used a spatial autoregressive model to analyze the correlation between wildfire smoke and COVID-19 outcomes at the county level.
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A 1-month lag showed an increase of 203 COVID-19 cases and 2.75 deaths per 10,000 persons per 10 µg/m3 of smoke exposure.
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The association between smoke exposure and COVID-19 cases diminished after 2 months, with no significant link to deaths.
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Findings suggest that wildfire smoke exposure likely exacerbated the spread of COVID-19 and increased mortality rates in 2020.

Open Forum Infectious Diseases

by Thomas C McHale, David R Boulware, Kelly Searle, Leda Kobziar, Phinehas Lampman, Julio C Zuniga-Moya, Ben Papadopoulos, Andrej Spec, Naomi E Hauser, George R Thompson
June 11, 2025

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