In a new study published on Friday, a team of researchers at Harvard University found evidence that exposure to elevated levels of fine particle pollution found in wildfire smoke may have led to thousands more cases of covid-19 and more deaths among those who tested positive for the coronavirus.
In some counties in California and Washington state hit particularly hard by wildfires last year, the study, published in the journal Science Advances, concluded that nearly 20 percent of the covid-19 cases were linked to elevated levels of wildfire smoke. The researchers also found that an even higher percentage of deaths could be linked to wildfire smoke in certain counties.
On its website, the U.S. Centers for Disease Control and Prevention says that wildfire smoke can irritate lungs and “make you more prone to lung infections, including SARS-CoV-2, the virus that causes COVID-19.”
A study published this year by scientists at the Desert Research Institute in Nevada found that the coronavirus positivity rate in Washoe County, Nev., increased significantly during periods of high wildfire smoke. The Harvard study sought to quantify the relationship across a wide range of counties in the American West.
To investigate the connection between smoke and covid-19, the researchers — from the Harvard T.H. Chan School of Public Health and the Harvard School of Engineering and Applied Sciences — developed statistical models that analyzed data from 92 counties in California, Oregon and Washington state where wildfires occurred between March and December 2020. In those three states, more than 73,000 people have died of covid-19 during the pandemic.