Boise Air Quality in March
Across 2019–2025, Boise's March air quality had a median AQI of 42 (Good) over 217 monitored days in the Boise City, ID area. 0.0% of March days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 58.5% of days. The cleanest March on record here was 2023 (median AQI 40, 0 days above 100) and the worst was 2021 (median 51, 0 days above 100, peak AQI 69).
- Good: 75.1%
- Moderate: 24.9%
- Unhealthy for Sensitive Groups: 0.0%
- 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.
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How is the air in Boise in March?
Good on a typical day: median AQI 42 across 2019–2025, with 0.0% of March days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓75.1% of March days were Good (AQI 0–50), 24.9% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the March peak was 69.
- ✓Best March: 2023; worst March: 2021.
Frequently asked questions
What is the air quality like in Boise in March?▾
Across 2019–2025, the median daily AQI in Boise in March was 42 (Good). 75.1% of days were Good, 24.9% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is March a good time for outdoor exercise in Boise?▾
A typical March day in Boise sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
Which pollutant causes Boise's March air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 58.5% of March days in Boise. The highest March AQI recorded in 2019–2025 was 69 (Moderate), in 2021.
Boise March air quality, year by year
Boise March 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 | 44 | 0 | 55 | PM2.5 |
| 2020 | 31 | 44 | 0 | 64 | PM2.5 |
| 2021worst | 31 | 51 | 0 | 69 | PM2.5 |
| 2022 | 31 | 43 | 0 | 64 | PM2.5 |
| 2023cleanest | 31 | 40 | 0 | 58 | O3 |
| 2024 | 31 | 41 | 0 | 54 | O3 |
| 2025 | 31 | 40 | 0 | 55 | O3 |
What March air means in Boise
A typical March day in Boise sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
March's median AQI of 42 is below Boise's whole-year median of 54, making it one of the area's cleaner periods. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so Boise runs in line with the national March norm; 0.0% of its March days topped AQI 100 versus 0.4% nationally (about the same).
March is part of Boise's spring season (March, April, May); the spring 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.