Widespread smoke has blanketed western Montana, creating unhealthy air conditions, according to state health officials.

The Montana Department of Environmental Quality issued an air quality alert Monday for Lincoln County due to elevated particulate concentrations. Air quality in Libby is currently “unhealthy,” according to the agency.

State and local health officials recommend people with respiratory illness or heart disease, the elderly and children avoid prolonged exertion. Everyone else should limit prolonged exertion, the agency stated. Another update will be posted at 4 p.m.

Numerous large wildfires in Washington, Oregon and Northern California are creating widespread smoke that is impacting the Pacific Northwest. The higher concentrations in Lincoln County are likely due to the Wolverine Creek fire in Washington, which is currently burning with extreme fire behavior and has consumed 16,000 acres.

A cold front is expected to move through the state later Monday as a low pressure system over British Columbia slowly moves eastward. The increase in winds, associated with the front, is expected to move in early this evening, potentially decreasing smoke impacts in Libby and moving eastward overnight.

The haze that was over the state throughout the weekend made its way down to the ground level in western Montana beginning Sunday, according to state officials. Particulate concentrations rapidly increased in many locations. The most significant impacts are in Lincoln County, where 24-hour average concentrations are currently unhealthy. Elsewhere, 24-hour average concentrations are currently unhealthy for sensitive groups in the Flathead Valley, Seeley Lake and Missoula, and moderate in Frenchtown, Helena, and Butte. Levels are also elevated to moderate in Broadus due to transported smoke and local fires.