AQI 45 · PM2.5 · Trend: Variable (wildfires)
| Average AQI | 45 |
| Good Days / Year | 230 |
| Unhealthy Days / Year | 18 |
| Primary Pollutant | PM2.5 |
| PM2.5 Average | 8 µg/m³ |
| Trend | — Variable (wildfires) |
| Monitoring Stations | 22 |
| Nonattainment Areas | 1 |
Montana's air quality is increasingly dominated by wildfire smoke, which can blanket mountain valleys for weeks. Missoula and other valley communities are particularly vulnerable. Billings has the state's highest industrial emissions from petroleum refining.
Montana DEQ Air Quality Bureau manages standards. Missoula has seasonal wood burning restrictions. Wildfire smoke management plans in development.
Libby — PM2.5 nonattainment (asbestos-contaminated vermiculite legacy from W.R. Grace mine, now primarily wood smoke). Missoula has historically been near nonattainment.