Smoke from widespread wildfires in Canada prompted air quality alerts across several Midwest and Northeast U.S. states this week.

There is an air quality alert for all counties in Michigan until midnight Friday, 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.

The smoke is expected to remain over the northern and central Plains of the United States for the next couple of days, according to meteorologists.