Ozone is the main concern that is causing an air quality alert Monday, the Minnesota Pollution Control Agency says — but what exactly is ozone?

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for west central, east central, central, south central, southwest, north central, and northwest Minnesota.

An air quality alert will be in effect from noon to 9 p.m. on Monday for much of the state, and dozens of counties are under a red flag warning.