Air quality alert issued for Twin Cities, St. Cloud, Rochester

The Minnesota Pollution Control Agency has issued an air quality alert for parts of Minnesota this weekend. The alert area includes an area surrounding St. Cloud, the Twin Cities, and Rochester. The alert is in effect from 6 p.m. Friday until noon Sunday.

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert due to fine particles for east-central and southeast Minnesota, effective Friday, February 19, at 6 p.m. through Sunday, February 21, at 12 p.m.. The affected area includes the Twin Cities metro, St. Cloud, Rochester, Albert Lea, Winona, and the tribal nation of Prairie Island.

Air quality is expected to worsen beginning Friday evening, with the Air Quality Index (AQI) forecasted to reach Orange or Unhealthy for Sensitive Groups category. Light winds and poor atmospheric mixing will produce an increased level of fine particles beginning Friday evening, through the overnight, and into Saturday. Southerly winds on Saturday will transport more fine particles into Minnesota through Sunday morning. This is expected to produce AQI values in the Orange or Unhealthy for Sensitive Groups category for the duration of the alert period. 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.

Temperature inversion aloft

Light winds and a temperature inversion a few thousand feet above ground level will create poor mixing conditions this weekend. That will trap pollutants near ground-level. The temperature inversion is created as mild Pacific air blows in above the colder air near the ground where we live.

Air quality readings are still in the moderate range Friday afternoon with a reading of 78 ppm in the Twin Cities.

But particulates are expected to increase to above 101 ppm this weekend. That’s unhealthy for sensitive groups such as people with asthma.

Plan accordingly this weekend.