A map of North America shows concentrations of particulate matter (PM2.5), the main pollutant in wildfire smoke, as depicted on the airnow.gov site July 17, 2023. AirNow.gov/Handout via REUTERS.
A map of North America shows concentrations of particulate matter (PM2.5), the main pollutant in wildfire smoke, as depicted on the airnow.gov site July 17, 2023. AirNow.gov/Handout via REUTERS.