SALEM, Ore. (AP) — The Oregon Department of Environmental Quality extended an air quality advisory for three southern Oregon counties that are dealing with smoke from wildfires, and added portions of Lake County in south-central Oregon.

The agency says the air quality was unhealthy Monday in much of Jackson, Josephine and Klamath counties. It was rated very unhealthy in the town of Shady Cove — a 35-minute drive north of Medford.

An unhealthy reading on the Air Quality Index means people should avoid prolonged or heavy exertion outdoors.