Billings Air Quality in 2024

In 2024, Billings's air quality (Billings, MT area) had a median daily AQI of 39 (Good) across 357 monitored days. 1 day (0.3%) reached Unhealthy for Sensitive Groups or worse, 272 were Good, and the year's peak AQI was 105 (Unhealthy for Sensitive Groups). Ground-level ozone set the daily AQI on 213 of those days. The cleanest month of 2024 was November (median AQI 31, 0 days above 100) and the worst was July (median 61, 1 day above 100, peak 105).

39
Median AQI
Good
1
Days above AQI 100
0.3% of 357 days
61
90th percentile AQI
worst 1 day in 10
105
Peak AQI
Unhealthy for Sensitive Groups
O3
Main pollutant
213 of 357 days
272
Good days
76.2% of days
  • Good: 76.2%
  • Moderate: 23.5%
  • Unhealthy for Sensitive Groups: 0.3%
  • Unhealthy or worse: 0.0%

Reduce Indoor Ozone in Billings

Today's main pollutant in Billings is ground-level ozone (AQI 21). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.

Recommended: Levoit Core 300True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft

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QUICK ANSWER

How was Billings's air quality in 2024?

Good on a typical day: median AQI 39, with 1 day above AQI 100 out of 357 monitored — the 2nd cleanest of 6 years on record for the area.

  • Peak AQI in 2024: 105 (Unhealthy for Sensitive Groups).
  • Ground-level ozone was the main pollutant on 213 days.
  • Cleanest month: November; worst: July.

Frequently asked questions

What was the average AQI in Billings in 2024?

EPA's Air Quality System puts Billings's (Billings, MT) median daily AQI for 2024 at 39, which is Good. 1 day were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 105.

Which month had the worst air quality in Billings in 2024?

The cleanest month of 2024 was November (median AQI 31, 0 days above 100) and the worst was July (median 61, 1 day above 100, peak 105).

Was 2024 a good or bad year for Billings's air?

Among the 6 years EPA has published for the area (2020–2025), 2024 ranks 2nd cleanest by days above AQI 100. 2024's median of 39 is in line with the area's typical annual median of 38.

Billings month by month in 2024

Billings air quality month by month, 2024 (Billings, MT, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
January3133058PM2.5
February2934044O3
March3137052O3
April3043064O3
May2440049O3
June3044061O3
Julyworst31611105O3
August3051072O3
September29390100PM2.5
October3139082PM2.5
Novembercleanest3031071PM2.5
December3135070PM2.5

How 2024 compares

Among the 6 years EPA has published for the area (2020–2025), 2024 ranks 2nd cleanest by days above AQI 100.

2024's median of 39 is in line with 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 21 (O3). 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.