Air quality alerts were in effect in Iowa, Minnesota, Wisconsin and Michigan, as well as eastern Nebraska and parts of Indiana and Illinois. Forecasters said the smoky skies would remain for much of the day. Canadian environmental officials said smoke from the forest fires would persist into Sunday for some areas.

There is an air quality alert for all of Southeast Michigan until midnight Saturday, the Michigan Department of Environment, Great Lakes and Energy reported. Pollutants across the state are expected to be in the Unhealthy for Sensitive Groups (USG, Orange AQI) range Wednesday and Thursday, with some locations reaching the Unhealthy (Red AQI) range.