An air quality alert remains in effect for the entire state of Minnesota on Monday. Smoke from Canadian wildfires prompted the alert, which is set to expire at 9 a.m. Tuesday. The northern half of the state will likely see the worst air quality.

An air quality alert will be in effect for all of Minnesota until at least 9 a.m. Aug. 12, according to the state Pollution Control Agency.

The return of wildfire smoke from fires burning in Canada has sparked another air quality alert in Minnesota, which will be in effect through Tuesday. The Minnesota Pollution Control Agency has placed the northern two-thirds of the state in the red alert zone, which means "unhealthy" for all residents, through 9 a.m. Tuesday.