Billings Air Quality in 2019
In 2019, Billings's air quality (Billings, MT area) had a median daily AQI of 31 (Good) across 292 monitored days. 1 day (0.3%) reached Unhealthy for Sensitive Groups or worse, 271 were Good, and the year's peak AQI was 159 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 292 of those days. The cleanest month of 2019 was May (median AQI 27, 0 days above 100) and the worst was July (median 32, 1 day above 100, peak 159).
- Good: 92.8%
- Moderate: 6.8%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.3%
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How was Billings's air quality in 2019?
Good on a typical day: median AQI 31, with 1 day above AQI 100 out of 292 monitored.
- ✓Peak AQI in 2019: 159 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 292 days.
- ✓Cleanest month: May; worst: July.
Frequently asked questions
What was the average AQI in Billings in 2019?▾
EPA's Air Quality System puts Billings's (Billings, MT) median daily AQI for 2019 at 31, which is Good. 1 day were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 159.
Which month had the worst air quality in Billings in 2019?▾
The cleanest month of 2019 was May (median AQI 27, 0 days above 100) and the worst was July (median 32, 1 day above 100, peak 159).
Billings month by month in 2019
Billings air quality month by month, 2019 (Billings, MT, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 34 | 0 | 56 | PM2.5 |
| February | 10 | 29 | 0 | 49 | PM2.5 |
| April | 8 | 20 | 0 | 45 | PM2.5 |
| Maycleanest | 31 | 27 | 0 | 70 | PM2.5 |
| June | 30 | 27 | 0 | 61 | PM2.5 |
| Julyworst | 29 | 32 | 1 | 159 | PM2.5 |
| August | 31 | 38 | 0 | 53 | PM2.5 |
| September | 30 | 28 | 0 | 53 | PM2.5 |
| October | 31 | 30 | 0 | 59 | PM2.5 |
| November | 30 | 31 | 0 | 50 | PM2.5 |
| December | 31 | 31 | 0 | 69 | PM2.5 |
How 2019 compares
2019's median of 31 is below the area's typical annual median of 38.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Billings
The latest EPA AirNow observation puts Billings's AQI at 25 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Billings air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Billings, MT), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.