COVID and wildfires

A recent analysis of COVID-19 and the 2020 wildfires in California, Oregon, and Washington estimated increases in COVID cases and mortality of about 20% associated with increased levels of fine particulate matter (PM2.5) based on satellite smoke observations. The study caught my eye for several reasons: PM2.5 is not “smoke,” the COVID-19 increases were not statistically significant, and a much simpler and transparent analysis of their data yielded different results. Here’s what I found.