Billings Air Quality in August
Across 2019–2025, Billings's August air quality had a median AQI of 42 (Good) over 216 monitored days in the Billings, MT area. 2.4% of August days (5 of 216) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 83.8% of days. The cleanest August on record here was 2023 (median AQI 27, 0 days above 100) and the worst was 2021 (median 62, 5 days above 100, peak AQI 167).
- Good: 66.7%
- Moderate: 31.0%
- Unhealthy for Sensitive Groups: 1.9%
- Unhealthy or worse: 0.5%
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.
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How is the air in Billings in August?
Good on a typical day: median AQI 42 across 2019–2025, with 2.4% of August days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓66.7% of August days were Good (AQI 0–50), 31.0% Moderate (51–100).
- ✓5 days of 216 reached AQI 101+; the August peak was 167.
- ✓Best August: 2023; worst August: 2021.
Frequently asked questions
What is the air quality like in Billings in August?▾
Across 2019–2025, the median daily AQI in Billings in August was 42 (Good). 66.7% of days were Good, 31.0% Moderate, and 2.4% reached Unhealthy for Sensitive Groups or worse, based on 216 monitored days in EPA's Air Quality System.
Is August a good time for outdoor exercise in Billings?▾
A typical August day in Billings sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 42 of August days (2.4%) reached AQI 101+ in 2019–2025.
Which pollutant causes Billings's August air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 83.8% of August days in Billings. The highest August AQI recorded in 2019–2025 was 167 (Unhealthy), in 2021.
Billings August air quality, year by year
Billings August air quality by year (Billings, MT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 38 | 0 | 53 | PM2.5 |
| 2020 | 31 | 41 | 0 | 96 | PM2.5 |
| 2021worst | 31 | 62 | 5 | 167 | PM2.5 |
| 2022 | 31 | 38 | 0 | 57 | PM2.5 |
| 2023cleanest | 31 | 27 | 0 | 70 | PM2.5 |
| 2024 | 30 | 51 | 0 | 72 | O3 |
| 2025 | 31 | 38 | 0 | 57 | O3 |
What August air means in Billings
A typical August day in Billings sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 42 of August days (2.4%) reached AQI 101+ in 2019–2025.
August's median AQI of 42 is above Billings's whole-year median of 38, making it one of the area's dirtier periods. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Billings runs in line with the national August norm; 2.4% of its August days topped AQI 100 versus 3.5% nationally (below average).
August is part of Billings's summer season (June, July, August); the summer page pools all three months.
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 month 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.