Billings Air Quality in 2020
In 2020, Billings's air quality (Billings, MT area) had a median daily AQI of 31 (Good) across 364 monitored days. 3 days (0.8%) reached Unhealthy for Sensitive Groups or worse, 304 were Good, and the year's peak AQI was 163 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 364 of those days. The cleanest month of 2020 was May (median AQI 21, 0 days above 100) and the worst was September (median 47, 2 days above 100, peak 126).
- Good: 83.5%
- Moderate: 15.7%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.3%
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How was Billings's air quality in 2020?
Good on a typical day: median AQI 31, with 3 days above AQI 100 out of 364 monitored — the 4th cleanest of 6 years on record for the area.
- ✓Peak AQI in 2020: 163 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 364 days.
- ✓Cleanest month: May; worst: September.
Frequently asked questions
What was the average AQI in Billings in 2020?▾
EPA's Air Quality System puts Billings's (Billings, MT) median daily AQI for 2020 at 31, which is Good. 3 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 163.
Which month had the worst air quality in Billings in 2020?▾
The cleanest month of 2020 was May (median AQI 21, 0 days above 100) and the worst was September (median 47, 2 days above 100, peak 126).
Was 2020 a good or bad year for Billings's air?▾
Among the 6 years EPA has published for the area (2020–2025), 2020 ranks 4th cleanest by days above AQI 100. 2020's median of 31 is below the area's typical annual median of 38.
Billings month by month in 2020
Billings air quality month by month, 2020 (Billings, MT, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 32 | 0 | 70 | PM2.5 |
| February | 29 | 27 | 0 | 53 | PM2.5 |
| March | 31 | 33 | 0 | 59 | PM2.5 |
| April | 30 | 31 | 0 | 52 | PM2.5 |
| Maycleanest | 31 | 21 | 0 | 39 | PM2.5 |
| June | 30 | 21 | 0 | 50 | PM2.5 |
| July | 31 | 30 | 1 | 163 | PM2.5 |
| August | 31 | 41 | 0 | 96 | PM2.5 |
| Septemberworst | 30 | 47 | 2 | 126 | PM2.5 |
| October | 31 | 42 | 0 | 72 | PM2.5 |
| November | 30 | 39 | 0 | 58 | PM2.5 |
| December | 29 | 32 | 0 | 62 | PM2.5 |
How 2020 compares
Among the 6 years EPA has published for the area (2020–2025), 2020 ranks 4th cleanest by days above AQI 100.
2020'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.