Boise Air Quality in 2019
In 2019, Boise's air quality (Boise City, ID area) had a median daily AQI of 51 (Moderate) across 365 monitored days. 3 days (0.8%) reached Unhealthy for Sensitive Groups or worse, 176 were Good, and the year's peak AQI was 170 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 264 of those days. The cleanest month of 2019 was April (median AQI 38, 0 days above 100) and the worst was December (median 63, 2 days above 100, peak 170).
- Good: 48.2%
- Moderate: 51.0%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.3%
Extra Protection for Boise Homes
Air quality in Boise is moderate (AQI 59), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How was Boise's air quality in 2019?
Moderate on a typical day: median AQI 51, with 3 days above AQI 100 out of 365 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2019: 170 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 264 days.
- ✓Cleanest month: April; worst: December.
Frequently asked questions
What was the average AQI in Boise in 2019?▾
EPA's Air Quality System puts Boise's (Boise City, ID) median daily AQI for 2019 at 51, which is Moderate. 3 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 170.
Which month had the worst air quality in Boise in 2019?▾
The cleanest month of 2019 was April (median AQI 38, 0 days above 100) and the worst was December (median 63, 2 days above 100, peak 170).
Was 2019 a good or bad year for Boise's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100. 2019's median of 51 is below the area's typical annual median of 54.
Boise month by month in 2019
Boise air quality month by month, 2019 (Boise City, ID, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 63 | 0 | 88 | PM2.5 |
| February | 28 | 54 | 0 | 90 | PM2.5 |
| March | 31 | 44 | 0 | 55 | PM2.5 |
| Aprilcleanest | 30 | 38 | 0 | 52 | O3 |
| May | 31 | 44 | 0 | 58 | PM2.5 |
| June | 30 | 44 | 0 | 77 | O3 |
| July | 31 | 49 | 0 | 100 | PM2.5 |
| August | 31 | 49 | 0 | 71 | PM2.5 |
| September | 30 | 39 | 0 | 64 | PM2.5 |
| October | 31 | 51 | 0 | 72 | PM2.5 |
| November | 30 | 71 | 1 | 104 | PM2.5 |
| Decemberworst | 31 | 63 | 2 | 170 | PM2.5 |
How 2019 compares
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100.
2019'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 59 (PM2.5). 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.