An air quality index of 300 or higher is considered hazardous, and the record-breaking smoke AQI in Grand Portage reached 800 on Tuesday.

The Minnesota Pollution Control Agency says additional air quality alerts are likely needed for much of Minnesota this weekend due to the heavy wildfire smoke in Canada moving into the upper Midwest.

An air quality map shows conditions improving in the U.S. on Friday as smoke from the Canadian wildfires subsides.