Haze over Lake Bemidji on July 20.
Nearly all of Minnesota is under an air quality alert as Canadian wildfire smoke moves into the area behind a northerly wind.
The only portion of the state not under alert is the North Shore.
Smoke is expected to remain over the area into Friday.
The air quality is considered unhealthy for sensitive groups, such as those with cardiovascular or respiratory health issues, children, and the elderly.
