As result of severe wildfires in Canada, Minnesota is facing the longest air quality alert on record since the Minnesota Pollution Control Agency began issuing alerts in 2008.

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.

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.