The Minnesota Pollution Control Agency has issued an air quality alert due to a rise in fine particles in east-central and southeast Minnesota, and area that includes the Twin Cities.
The alert went into effect at 6 p.m. Friday and will remain in place until noon Sunday, with the affected area also including St. Cloud, Rochester, Albert Lea, Winona, and the tribal nation of Prairie Island.
The cause of the pollution alert is "light winds and poor atmospheric mixing," which has contributed to the increased levels of particles.
The MPCA says air quality values will be in the "Orange" alert level, meaning it will be unhealthy for sensitive groups.
This group includes those with asthma or other breathing conditions, children and older adults, those with heart disease or high blood pressure, and those doing extended physical activity outdoors.
"Air quality will gradually improve Sunday morning as a weather disturbance moves across Minnesota, which will improve dispersion and bring in cleaner air from the west," the MPCA says.
The MPCA is advising people reduce vehicle trips, postpone the use of gas-powered garden equipment, and avoid backyard fires during the alert.
Here's Bring Me The News meteorologist Sven Sundgaard explaining why air quality alerts are issued even during the winter.