Air Quality Alerts Issued in Multiple States Due to Ozone Pollution.

An air quality alert is in effect until 9 p.m. Thursday for central and southern Minnesota, including the Twin Cities, due to elevated levels of ground-level ozone caused by pollutants transported by southerly winds from the Chicago area, northeast Iowa, and southeast Minnesota. The ozone levels are expected to reach the orange air quality index category, considered unhealthy for sensitive groups. The forecast calls for slight improvements in air quality over the next few days, but wildfire smoke from Ontario may cause particulate AQIs to reach orange in parts of northeast Minnesota over the weekend.