MARSHALL – The Minnesota Pollution Control Agency (MPCA) has issued an Air Quality Alert for ozone pollution in southwest Minnesota from noon today (Tuesday) until 9:00 p.m. Thursday, but this time Canadian wildfires aren’t to blame.

Ground-level ozone is expected to be high during the afternoon hours on Tuesday, Wednesday, and Thursday across southwest Minnesota. Sunny skies, warm temperatures, and low humidity will create an environment favorable for two types of pollutants (Volatile Organic Compounds and Nitrogen Oxides) to react in the air to produce ground-level ozone. These pollutants will be transported by southerly winds from the Chicago area, northeast Iowa, and southeast Minnesota. Ozone will be highest during the afternoon and early evening hours when sunshine is most abundant, and temperatures are highest. Ozone will be low in the morning, late evening, and overnight.  

Ozone levels are expected to reach the orange air quality index (AQI) category, a level considered unhealthy for sensitive groups, across southwest Minnesota. The alert area includes Marshall and Worthington. Sensitive groups, such as people with lung disease (including asthma), heart disease, children and older adults, and people who are active outdoors, may experience health effects.

Reduce or eliminate activities that contribute to air pollution, such as outdoor burning, and use of residential wood burning devices. Reduce vehicle trips and vehicle idling as much as possible.