“The especially long-lived ozone holes during 2020-2022 fit squarely into this picture, as the size/depth of the hole during October was particularly notable in all three years.” ...

Ground-level ozone concerns prompt air quality alert in Minnesota 01:33. The Minnesota Pollution Control Agency says ozone is the main concern that is triggering an air quality alert on Monday.

The Minnesota Pollution Control Agency issued an air quality alert for the southern half of the state Tuesday due to "ground-level ozone." Here's what that means.