Boise Air Quality in July
Across 2019–2025, Boise's July air quality had a median AQI of 59 (Moderate) over 217 monitored days in the Boise City, ID area. 12.9% of July days (28 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 56.2% of days. The cleanest July on record here was 2019 (median AQI 49, 0 days above 100) and the worst was 2024 (median 101, 17 days above 100, peak AQI 214).
- Good: 24.9%
- Moderate: 62.2%
- Unhealthy for Sensitive Groups: 11.1%
- Unhealthy or worse: 1.8%
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 is the air in Boise in July?
Moderate on a typical day: median AQI 59 across 2019–2025, with 12.9% of July days above AQI 100. Ground-level ozone is the main driver.
- ✓24.9% of July days were Good (AQI 0–50), 62.2% Moderate (51–100).
- ✓28 days of 217 reached AQI 101+; the July peak was 214.
- ✓Best July: 2019; worst July: 2024.
Frequently asked questions
What is the air quality like in Boise in July?▾
Across 2019–2025, the median daily AQI in Boise in July was 59 (Moderate). 24.9% of days were Good, 62.2% Moderate, and 12.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is July a good time for outdoor exercise in Boise?▾
A typical July day in Boise is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of July days (12.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Boise's July air quality problems?▾
Ground-level ozone set the daily AQI on 56.2% of July days in Boise. The highest July AQI recorded in 2019–2025 was 214 (Very Unhealthy), in 2024.
Boise July air quality, year by year
Boise July air quality by year (Boise City, ID, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 49 | 0 | 100 | PM2.5 |
| 2020 | 31 | 54 | 1 | 152 | PM2.5 |
| 2021 | 31 | 80 | 8 | 136 | O3 |
| 2022 | 31 | 66 | 1 | 114 | O3 |
| 2023 | 31 | 56 | 1 | 102 | O3 |
| 2024worst | 31 | 101 | 17 | 214 | O3 |
| 2025 | 31 | 51 | 0 | 93 | O3 |
What July air means in Boise
A typical July day in Boise is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of July days (12.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
July's median AQI of 59 is above Boise's whole-year median of 54, making it one of the area's dirtier periods. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so Boise runs above the national July norm; 12.9% of its July days topped AQI 100 versus 3.6% nationally (above average).
July is part of Boise's summer season (June, July, August); the summer page pools all three months.
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 month 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.