Nevada study says wildfire smoke may add to COVID-19 risk

A study published last week by scientists at the Desert Research Institute found that coronavirus infection rates increased disproportionately during wildfire season in 2020, when smoke from fires in neighboring states blanketed much of northern Nevada.

In a paper in the Journal of Exposure Science & Environmental Epidemiology, Desert Research Institute Assistant Research Scientist Daniel Kiser and four co-authors note the test positivity rate in Washoe County increased significantly during periods when monitors measured high levels of particulate matter in the air from wildfire smoke.

For every 10 micrograms per cubic meter of small particulate matter known as PM2.5 in the air, the positivity rate increased about 6.3 percent two to six days later, the study found.

Kiser said the study was observational and noted that the uptick could be attributed to other factors, like last year’s second surge, students returning to schools or changes in local restrictions. But he said momentary upticks during periods of high pollution suggested a connection between smoke and the spread of the virus.

“That temporary association in the midst of a large uptick in cases overall is what convinced us that something’s going on,” he told the Associated Press.

The authors argued that the association between wildfire smoke and the coronavirus likely suggested pollution made people more prone to viruses more broadly.

“Our findings also bolster arguments that PM2.5 from other sources such as vehicle traffic or industry, increases susceptibility to” the coronavirus, they wrote.

Kiser said wildfires and other climate change-driven weather events were likely to figure more largely into the study of viruses in the future.

Smoke from the Tamarack Fire and Beckwourth Complex Fire is shrouding parts of northern Nevada, causing pollution in Reno, Carson City and Gardnerville.