Temperatures near 90 degrees, western wildfire smoke and sunshine will combine on Thursday to make the air unhealthy for some people in parts of eastern and central Minnesota.
The Minnesota Pollution Control Agency on Wednesday posted an air quality alert effective from noon to 8 p.m. on Thursday. The affected area includes the Twin Cities metro, St. Cloud, Hinckley and the Tribal Nation of Mille Lacs.
People who might be affected include those with asthma, chronic bronchitis, emphysema and other breathing conditions. People of all ages doing extended or heavy, physical activity, including sports or working outdoors, could also experience problems.
The worst conditions are expected during the afternoon and early evening across the Twin Cities metro area into central Minnesota, the MPCA said in a statement. Ozone values should return to moderate levels as the sun sets Thursday evening, though "wildfire smoke will continue to keep fine particle levels elevated in the yellow category after ozone decreases.
Unhealthy ozone levels can aggravate lung diseases and may make it harder to breathe. It may also cause throat soreness, wheezing, coughing or unusual fatigue, the agency said.