The Minnesota Pollution Control Agency has issued an air quality alert for northwest Minnesota due to dangerous conditions caused by wildfire smoke. The air quality index (AQI) is expected to reach the purple level, meaning the air is very unhealthy for everyone.

During this time, all people should avoid prolonged or heavy exertion outdoors, and sensitive groups, such as people with asthma and lung disease, heart disease, children and older adults, should avoid all physical activities outdoors.

The alert is expected to remain in effect through 6 a.m. Thursday, July 22.

According to the alert, hazardous conditions were created overnight when northerly winds blew smoke from wildfires in Ontario and Manitoba into Minnesota overnight.

Conditions are expected to improve somewhat by Thursday morning as winds continue to blow the smoke out of the state, and the AQI is expected to drop to the red level, or unhealthy for all individuals, by Thursday.