The Minnesota Pollution Control Agency has issued an air quality alert until 4 p.m. Tuesday covering northern and central Minnesota.

The unhealthy air is due to a band of smoke from wildfires burning in Canada. The alert covers the northern half of the state, including Moorhead, Brainerd and Duluth, and as far south as Hinckley, Ortonville and Alexandria.

The Minnesota Pollution Control Agency says particle levels are expected to reach the orange air quality index category. That’s considered unhealthy for sensitive groups, including people with asthma or other breathing conditions; people who have heart disease, high blood pressure or diabetes; pregnant people and children and older adults.