Air quality across many parts of Montana is currently rated at levels ranging from "unhealthy for sensitive groups" to "hazardous."
The cause of the poor air quality is smoke pouring in to Montana from wildfires in several western states, including Oregon and California.
On Monday morning, the Montana Department of Environmental Quality reports that the following areas have air quality that is unhealthy: Bozeman, Butte, Missoula, Kalispell, and Lewistown.
Air quality in Great Falls and Helena is currently listed as being unhealthy for sensitive groups. Air quality in the Libby region is listed as hazardous, and very unhealthy in Thompson Falls.
Areas along the Hi-Line east of the Divide remain largely unaffected, with air quality listed as good.
Here is an explanation from MT DEQ about the different categories:
- HAZARDOUS: All children and adults should avoid or limit all outdoor exertion
- VERY UNHEALTHY: Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion
- UNHEALTHY: 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
- UNHEALTHY FOR SENSITIVE GROUPS: Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion
- MODERATE: Unusually sensitive people should consider limiting prolonged outdoor exertion
From the MT DEQ website on Monday morning:
Smoke has been moving into Montana from wildfires in Idaho, Washington, and Oregon. Air quality has reached HAZARDOUS in Libby, VERY UNHEALTHY in Thompson Falls, and UNHEALTHY in the Flathead Valley. Seeley Lake and Hamilton have both reported air quality levels at UNHEALTHY FOR SENSITIVE GROUPS. Other sites around the state are reporting GOOD or MODERATE air quality, but may worsen as the day continues.
Upper-level winds will continue to steer smoke into Montana today and Monday. A ridge of high pressure is building and moving into Montana, which will continue the same pattern of westerly flow and calm weather. In other words, it is unlikely that air quality will improve significantly today or Monday.