Smoke from the more than 700 wildfires burning in Canada is continuing to blanket parts of the Midwest for a final day.

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.