The Colorado Department of Health and Environment has issued an air quality advisory for a large part of Western Colorado, including Montezuma, Dolores and La Plata counties.

Widespread smoke from in-state and out-of-state is expected through Wednesday morning. The biggest impact will be felt in areas near the Bull Draw Fire at the Montrose/Mesa county line, the Cabin Lake Fire in Rio Blanco County and the Silver Creek Fire near the Routt/Grand county line.

Additional fire activity also is possible near the Plateau Fire near the Dolores/Montezuma county line.

The affected area ranges from Moffat County in the northwest to Montezuma County in the southwest and Chaffee County in the east. Towns include Dove Creek, Cortez, Dolores, Mancos, Durango, Telluride and Ouray.

The advisory runs through 9 a.m. Wednesday.

Air quality in the Four Corners – and most of the state – currently is rated moderate, meaning that it is at an acceptable level. On a scale that rates air quality from 0 to 500, a “moderate” rating runs from 51 to 100. An “unhealthy” rating runs from 151 to 200, and a “hazardous” rating runs from 301 to 500.

The most affected residents are the very young, the elderly and those with heart disease or respiratory illnesses. Generally, if visibility is less than 5 miles in smoke in your neighborhood, smoke has reached levels that have become unhealthy, the Department of Health and Environment said.