An air quality health advisory has been issued for the southern two-thirds of Wisconsin until noon Thursday.
The state Department of Natural Resources says the advisory is in effect south of a line from St. Croix County through Taylor County and Oconto County to Door County.
The agency says it acted because of persistent elevated levels of fine particles in the air. It says they come primarily from sources such as power plants, factories and other industrial sources, vehicle exhaust and wood fires.
The public is being asked to reduce driving when possible in the area, as well as to postpone activities that use small gasoline and diesel engines, minimize outdoor wood fires and practice electrical energy conservation.
The D-N-R says the air quality is expected by gradually improve in the area byThursday afternoon.