The Lincoln County Environmental Health Department is asking Libby-area residents to not use wood burning stoves on Tuesday evening if an alternate heat source is available.

Erik Leigh, environmental technician, said poor ventilation and weather conditions led to a local inversion on Tuesday. As of late afternoon, critical levels had not been reached and Leigh said that conditions improved slightly throughout the day.

“But we would like to ask that you please refrain from using your woodstoves if you have any alternate heat source,” Leigh said. “We believe that air quality may continue to decline. If it does, we will be forced to issue an air quality alert during which area residents would be unable to use any wood burning heat sources.”

An air quality alert was issued on one occasion in the Libby area last year.

As of 4:30 p.m. Tuesday, Leigh said that the department is asking for voluntary use of an alternate heat source through the night.

The state has issued a stagnation watch for Libby, Whitefish and Kalispell.

According to John Coefield, meteorologist with the Montana Department of Environmental Quality’s Air Resource Management Bureau, particulate levels are expected to rise overnight under very strong inversion in the western valleys.

“I am expecting some relief in the afternoon again tomorrow (Wednesday) as the forecast dispersion is slightly better but with the residual smoke still hanging around, overall particulate levels are expected to be higher tomorrow than today," Coefield said in an air quality update available on the agency's website .

Coefield added that Libby’s levels are expected to be “unhealthy for sensitive groups” again on Wednesday afternoon – a caution that also existed for a few hours on Tuesday. Under that category, people with respiratory or heart disease, the elderly and children are cautioned to limit prolonged exertion.

For the latest air quality updates from Montana DEQ, go to: http://svc.mt.gov/deq/aqreport/mostRecentUpdate.aspx .