Is the Air Quality Good in Powder River, Montana?
Mostly — air quality in Powder River, Montana is fair, not pristine. The city earns a Grade of C (fair) on a 5-year median AQI of 41 (Good), with 36 unhealthy-air days over five years (about 7 per year). Healthy adults are fine most of the time, but sensitive groups should watch the daily forecast.
Who Can Safely Breathe the Air in Powder River, Montana?
Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
Across the past five years, this area has logged 36 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 7 days per year. That is roughly typical for a U.S. metro, with most caution days clustered in summer (ozone) or wildfire season.
Powder River, Montana Air Quality Snapshot
| Air Quality Grade | C60/100 |
| 5-Year Median AQI | 41 (Good) |
| Most Recent Median AQI (2023) | 44 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Worsening (+0.34 AQI/yr) |
| Unhealthy Days (last 5 yr) | 36 |
| National Rank (cleanest = #1) | #543 of 1,020 (53th most polluted percentile) |
| Montana Rank | #16 of 19 |
What Does the C Grade Mean?
Powder River, Montana earns a C — air quality is fair, but not great. With a 5-year median AQI of 41, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.
Powder River, Montana's 5-year median AQI of 41 is right around the national average of 41 across the 1,020 monitored U.S. cities tracked here. Within Montana, Powder River, Montana runs more polluted than the state average of 31 — local sources or geography are concentrating pollution above the state's typical reading.
For context within Montana: Rosebud, Montana currently holds the state's cleanest grade (A, AQI 23), while Sanders, Montana sits at the bottom (D, AQI 36).
What's in Powder River, Montana's Air?
The dominant pollutant in Powder River, Montana is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 215 | 61% |
| Fine Particulate Matter (PM2.5) | 108 | 30% |
| Coarse Particulate Matter (PM10) | 31 | 9% |
| Nitrogen Dioxide | 1 | 0% |
Is the Air Getting Better or Worse?
Air quality in Powder River, Montana has been getting worse over the past decade, with median AQI climbing by roughly 0.3 points per year. That bucks the national trend of broad improvement, and most often reflects either growing wildfire smoke exposure (particularly across the West) or rising local emissions from population and freight growth.
In 2014, Powder River, Montana posted a median AQI of 38. By 2023 that figure was 44 — a rise of 6 AQI points dirtier across 10 years of EPA records.
Year-by-Year AQI in Powder River, Montana
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 38 | 286 | 1 | Ozone |
| 2015 | 40 | 274 | 6 | Ozone |
| 2016 | 39 | 299 | 0 | Ozone |
| 2017 | 42 | 243 | 9 | Ozone |
| 2018 | 41 | 272 | 4 | Ozone |
| 2019 | 38 | 312 | 1 | Ozone |
| 2020 | 41 | 254 | 5 | Ozone |
| 2021 | 42 | 230 | 15 | Ozone |
| 2022 | 39 | 292 | 3 | Ozone |
| 2023 | 44 | 244 | 12 | Ozone |
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Powder River, Montana
Powder River, Montana has an Air Quality Grade of C (fair) with a 5-year median AQI of 41. The dominant pollutant is Ground-Level Ozone, and air quality has been worsening over the past decade.
This answer pulls from the EPA Air Quality System (AQS), the authoritative federal source for U.S. air quality and pollution monitoring. The headline number above is the direct answer; what follows is the additional context most readers need to use the answer for a real decision rather than just a fact lookup.
For readers turning this answer into action: cross-reference against the underlying the EPA Air Quality System (AQS) record before acting on time-sensitive decisions. The site renders the data as it was published; subsequent revisions can shift the picture, and the live federal data is always the authoritative current reference.
Source: EPA Outdoor Air Quality Data, 2026.