Boise Air Quality in 2025
In 2025, Boise's air quality (Boise City, ID area) had a median daily AQI of 51 (Moderate) across 365 monitored days. 1 day (0.3%) reached Unhealthy for Sensitive Groups or worse, 182 were Good, and the year's peak AQI was 135 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 206 of those days. The cleanest month of 2025 was March (median AQI 40, 0 days above 100) and the worst was December (median 60, 1 day above 100, peak 135).
- Good: 49.9%
- Moderate: 49.9%
- Unhealthy for Sensitive Groups: 0.3%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Boise
Today's main pollutant in Boise is ground-level ozone (AQI 38). 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 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How was Boise's air quality in 2025?
Moderate on a typical day: median AQI 51, with 1 day above AQI 100 out of 365 monitored — the 1st cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 135 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 206 days.
- ✓Cleanest month: March; worst: December.
Frequently asked questions
What was the average AQI in Boise in 2025?▾
EPA's Air Quality System puts Boise's (Boise City, ID) median daily AQI for 2025 at 51, which is Moderate. 1 day were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 135.
Which month had the worst air quality in Boise in 2025?▾
The cleanest month of 2025 was March (median AQI 40, 0 days above 100) and the worst was December (median 60, 1 day above 100, peak 135).
Was 2025 a good or bad year for Boise's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 1st cleanest by days above AQI 100 — the best year on record here. 2025's median of 51 is below the area's typical annual median of 54.
Boise month by month in 2025
Boise air quality month by month, 2025 (Boise City, ID, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 54 | 0 | 82 | PM2.5 |
| February | 28 | 54 | 0 | 74 | PM2.5 |
| Marchcleanest | 31 | 40 | 0 | 55 | O3 |
| April | 30 | 50 | 0 | 80 | O3 |
| May | 31 | 61 | 0 | 97 | O3 |
| June | 30 | 48 | 0 | 80 | O3 |
| July | 31 | 51 | 0 | 93 | O3 |
| August | 31 | 43 | 0 | 84 | O3 |
| September | 30 | 52 | 0 | 97 | PM2.5 |
| October | 31 | 43 | 0 | 65 | PM2.5 |
| November | 30 | 55 | 0 | 70 | PM2.5 |
| Decemberworst | 31 | 60 | 1 | 135 | PM2.5 |
How 2025 compares
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 1st cleanest by days above AQI 100 — the best year on record here.
2025's median of 51 is below the area's typical annual median of 54.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Boise
The latest EPA AirNow observation puts Boise's AQI at 38 (O3). The figures above are multi-year annual statistics, not today's reading.
View current Boise air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Boise City, ID), 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.