Wildfire smoke from the Prairies prompted special air quality statements and warnings across the country Saturday.

The Air Quality Index (AQI), a system used to communicate how much pollution is in the air, is expected to reach the red or unhealthy category in a large swath of Minnesota, and will likely remain so through Saturday.

Smoke from wildfires blazing across Canada is once again wafting over huge portions of the U.S. Midwest and worsening air quality there. On August 1 conditions are particularly bad in Minnesota, Iowa and Illinois.