SPOKANE, Wash. -- An Air Stagnation Advisory is in effect for most of Central Washington and has now been extended to Northeast Washington until 12:00 p.m. on Thursday. The stagnant air comes as a result of the high-pressure system that is over the region, causing cold air to be trapped beneath a layer of warmer air. The warm air holds in any pollutants – smoke from fires or cars, dust, or dirt – and prevents them from escaping or spreading. This stagnant air holds in pollutants and causes poorer air quality. Other factors include a lack of precipitation and wind in the region, both of which come as a result of the high pressure around most of Washington State.

The advisory that warns of moderate to unhealthy air spans Douglas, Grant, Chelan, Okanogan, and Stevens counties, among others. It’s expected that as the air stays stagnant, that pollutants may build up, leading to poorer air for later in the week on Wednesday and Thursday.

While Spokane County is not under the Air Stagnation Advisory, forecasts suggest that air quality in Spokane on Wednesday will be Unhealthy for Sensitive Groups. People who suffer from respiratory problems should limit outdoor activity through Thursday.

The Spokane Regional Clean Air Agency has said if air quality continues to degrade, they may issue burn bans for affected areas. Burn bans prevent more pollutants from being trapped in the stagnant air. If you are part of an affected demographic, especially those with respiratory illnesses, it is suggested you contact your physician for help dealing with high levels of air pollution.