Boise Air Quality in October
Across 2019–2025, Boise's October air quality had a median AQI of 49 (Good) over 217 monitored days in the Boise City, ID area. 6.9% of October days (15 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 88.5% of days. The cleanest October on record here was 2025 (median AQI 43, 0 days above 100) and the worst was 2024 (median 63, 11 days above 100, peak AQI 194).
- Good: 50.7%
- Moderate: 42.4%
- Unhealthy for Sensitive Groups: 4.6%
- Unhealthy or worse: 2.3%
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
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Boise in October?
Good on a typical day: median AQI 49 across 2019–2025, with 6.9% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓50.7% of October days were Good (AQI 0–50), 42.4% Moderate (51–100).
- ✓15 days of 217 reached AQI 101+; the October peak was 194.
- ✓Best October: 2025; worst October: 2024.
Frequently asked questions
What is the air quality like in Boise in October?▾
Across 2019–2025, the median daily AQI in Boise in October was 49 (Good). 50.7% of days were Good, 42.4% Moderate, and 6.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Boise?▾
A typical October day in Boise sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 14 of October days (6.9%) reached AQI 101+ in 2019–2025.
Which pollutant causes Boise's October air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 88.5% of October days in Boise. The highest October AQI recorded in 2019–2025 was 194 (Unhealthy), in 2024.
Boise October air quality, year by year
Boise October air quality by year (Boise City, ID, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 51 | 0 | 72 | PM2.5 |
| 2020 | 31 | 55 | 3 | 158 | PM2.5 |
| 2021 | 31 | 45 | 0 | 66 | PM2.5 |
| 2022 | 31 | 58 | 0 | 98 | PM2.5 |
| 2023 | 31 | 39 | 1 | 120 | PM2.5 |
| 2024worst | 31 | 63 | 11 | 194 | PM2.5 |
| 2025cleanest | 31 | 43 | 0 | 65 | PM2.5 |
What October air means in Boise
A typical October day in Boise sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 14 of October days (6.9%) reached AQI 101+ in 2019–2025.
October's median AQI of 49 is below Boise's whole-year median of 54, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Boise runs above the national October norm; 6.9% of its October days topped AQI 100 versus 1.3% nationally (above average).
October is part of Boise's fall season (September, October, November); the fall 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.