The Montana Department of Environmental Quality issued an air quality alert covering large portions of the state that remains in effect until 9 a.m. on Aug. 11, 2026, citing rising concentrations of fine particulate matter linked to wildfire smoke.
Scope of the alert
State officials say the advisory applies to the following counties: Beaverhead, Broadwater, Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Lake, Lewis and Clark, Lincoln, Madison, Mineral, Missoula, Park, Powell, Ravalli, Silver Bow, Sweet Grass, Sanders and Yellowstone. The alert warns that airborne particle levels have been trending upward and that a short-term exceedance of the federal 24-hour air quality standard is either occurring or may occur.
Air-monitoring sites across Montana are reporting differing levels of concern. As of early Monday readings:
- Unhealthy conditions were reported in Columbia Falls, Frenchtown, Libby and Missoula.
- Unhealthy for sensitive groups was observed in Billings, Dillon, Great Falls, Helena and Thompson Falls.
- Moderate particulate levels were measured in Butte, Cut Bank, Hamilton, Lewistown and Sleeping Giant.
Who should take precautions
Health officials emphasize that when particulate matter reaches these levels, certain populations face heightened risk. The state recommends that:
- People with heart or lung disease, older adults and children should avoid extended outdoor exertion when conditions are Unhealthy.
- Those same groups should reduce prolonged exertion when conditions reach Unhealthy for sensitive groups.
- Individuals who are unusually sensitive to air pollution should consider curtailing strenuous outdoor activity when air quality is Moderate.
Practical steps residents can take
Montanans seeking to reduce exposure to smoke-related particles can follow several common-sense measures recommended by public health authorities:
- Limit vigorous outdoor exercise, especially during the worst hours of smoke haze.
- Keep windows and doors closed and run air-conditioning on recirculate where available to limit infiltration of outdoor air.
- Use certified HEPA air cleaners indoors when possible; avoid activities that increase indoor particle levels, such as smoking or frying foods at high heat.
- People who must be outdoors and are at high risk should consider N95 or KN95 masks, which filter fine particles more effectively than cloth coverings.
- Monitor local air-quality updates and follow guidance from health care providers if you have respiratory or cardiac conditions.
Monitoring the situation
The Department of Environmental Quality directs residents to the state’s online air-quality portal for the latest readings and maps. The site provides current conditions at monitoring locations across Montana and offers tools for tracking particulate concentrations hour-by-hour.
| Category | Communities |
|---|---|
| Unhealthy | Columbia Falls, Frenchtown, Libby, Missoula |
| Unhealthy for sensitive groups | Billings, Dillon, Great Falls, Helena, Thompson Falls |
| Moderate | Butte, Cut Bank, Hamilton, Lewistown, Sleeping Giant |
Officials note that smoke patterns can change quickly with shifting winds and fire behavior. Residents in affected areas should be prepared for conditions to improve or deteriorate over the course of the day and into Tuesday morning.
For continuous updates and localized readings, the Department of Environmental Quality maintains an online portal at todaysair.mtdeq.us.
State and local health authorities continue to monitor conditions and will issue further advisories if particulate concentrations approach more severe thresholds.
