The Minnesota Pollution Control Agency is watching a stagnant weather pattern over southern Minnesota that is increasing air pollution.
The MPCA has issued an air advisory through midday Saturday for the southern two-thirds of Minnesota because of increased levels of fine-particle pollution. There's not enough wind to disperse the particles, and the snow melt adds to the problem.
Cassie McMahon, air pollution research analyst for the MPCA, said that added moisture in the air tends to hold pollution in place. The bad air could cause problems for certain groups, she said.
"That includes people with pre-existing respiratory or cardiovascular disease," McMahon said.
Fine-particle pollution is produced mainly from combustion, including vehicle or equipment exhaust and wood burning.