Thousands of COVID-19 cases and hundreds of deaths of those who tested positive for coronavirus in California, Oregon, and Washington last year may be attributable to increases in fine particulate air pollution from wildfire smoke, a new study shows.
Researchers at Harvard University estimated that there were 20,000 additional COVID-19 infections and 750 deaths linked with exposure to wildfire smoke between March and December 2020 in the western states, the New York Times reports. The study, which was published last week in the journal Science Advances, is the first to show a statistical link between wildfire smoke and COVID-19 cases and deaths.
Fine particulate matter, or PM 2.5, is among the tiniest but most dangerous pollutants. Exposure to PM 2.5, specifically from wildfires, can lead to a number of health complications including asthma, heart disease, chronic bronchitis, and other respiratory illnesses. These are all underlying conditions that make people vulnerable to COVID-19.
“Fine particulate matter air pollution can be an additional vehicle for spreading the virus even faster,” Francesca Dominici, co-author of the study and professor of biostatistics, population and data science at Harvard T.H. Chan School of Public Health, told CNN.
“Considering that we are seeing an increased risk of cases from the Delta [variant] and we already have the wildfires, that’s going to be concerning,” she said.
Harvard researchers looked at 92 counties in California, Oregon, and Washington impacted by wildfire last year. Using satellite images for the fires and public data on COVID-19 cases and deaths in the three states, researchers found that in the majority of the counties they studied, there was strong evidence that the more smoke there was, the more there were COVID-19 cases and deaths.
The study’s findings add to well-established data on the connection between air pollution and respiratory infections and conditions.
“These results provide strong evidence that, in many counties, the high levels of PM2.5 that occurred during the 2020 wildfires substantially exacerbated the health burden of COVID-19,” the authors wrote.
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