The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for northern Minnesota. The alert takes effect Tuesday, May 16, beginning at 4 a.m. and runs until Tuesday, May 16, at 4 p.m. The affected area includes the northern half of Minnesota, and the tribal nations of Grand Portage, Fond du Lac, Leech Lake, Red Lake, and Mille Lacs.
A band of smoke from wildfires in northern Alberta and Saskatchewan is currently moving east across Ontario. A strong cold front will dive south overnight and begin pulling this smoke south towards Minnesota. Sinking air behind the front will bring this smoke to the surface.
Smoke will cross the Canadian border into northern Minnesota around 4 a.m. Tuesday. Northerly winds will push the smoke as far south as Hinckley and Alexandria by Tuesday afternoon. Air quality should improve across northeast Minnesota Tuesday afternoon. Smoke may linger across northwest Minnesota through Tuesday.
Fine particle levels are expected to reach the orange air quality index (AQI) category, a level considered unhealthy for sensitive groups, across northern Minnesota. This area includes Ely, International Falls, Roseau, Duluth, Brainerd, Moorhead, and the tribal nations of Grand Portage, Fond du Lac, Leech Lake, Red Lake, and Mille Lacs. In the orange area, sensitive groups should avoid prolonged time outdoors.
What this alert means
Air moves long distances and carries pollutants. During air quality alerts due to wildfires, the air is mixed with harmful smoke. Wildfire smoke spreads or lingers depending on the size of the fires, the wind, and the weather.
The air quality index (AQI) is color-coded. Air quality alerts are issued when the AQI is forecast to reach an unhealthy level, which includes forecasts in the orange, red, purple, and maroon categories. For a full description of each air quality category, visit airnow.gov.