Air quality in Northwest Montana was expected to go from bad to worse Sunday into Monday as smoke from Western wildfires impacts the region.

Montana DEQ rated air quality as hazardous Sunday in Lincoln County where visibility was generally less than 1 mile.

The DEQ warned that under a hazardous rating "all children and adults should avoid or limit all outdoor exertion."

Air quality in the Flathead Valley was rated slightly better Sunday as "unhealthy," but was expected to worsen into Monday.

Under an unhealthy rating "active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion," the DEQ warned.

An Air Quality Alert was in effect for Flathead, Granite, Lake, Lincoln, Mineral, Missoula, Powell, Ravalli and Sanders counties.

Montana DEQ noted that smoke from fires burning in Idaho, Washington and Oregon will continue to push east this week.

The National Weather Service reports that a low pressure system will make its way across the Pacific Northwest by next weekend. Cooler temperatures and some rain is expected.