Boise Air Quality in 2023

In 2023, 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, 180 were Good, and the year's peak AQI was 120 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 197 of those days. The cleanest month of 2023 was March (median AQI 40, 0 days above 100) and the worst was July (median 56, 1 day above 100, peak 102).

51
Median AQI
Moderate
3
Days above AQI 100
0.8% of 365 days
68
90th percentile AQI
worst 1 day in 10
120
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
197 of 365 days
180
Good days
49.3% of days
  • Good: 49.3%
  • Moderate: 49.9%
  • Unhealthy for Sensitive Groups: 0.8%
  • Unhealthy or worse: 0.0%

Extra Protection for Boise Homes

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QUICK ANSWER

How was Boise's air quality in 2023?

Moderate on a typical day: median AQI 51, with 3 days above AQI 100 out of 365 monitored — the 3rd cleanest of 7 years on record for the area.

  • Peak AQI in 2023: 120 (Unhealthy for Sensitive Groups).
  • Fine particulate matter (PM2.5) was the main pollutant on 197 days.
  • Cleanest month: March; worst: July.

Frequently asked questions

What was the average AQI in Boise in 2023?

EPA's Air Quality System puts Boise's (Boise City, ID) median daily AQI for 2023 at 51, which is Moderate. 3 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 120.

Which month had the worst air quality in Boise in 2023?

The cleanest month of 2023 was March (median AQI 40, 0 days above 100) and the worst was July (median 56, 1 day above 100, peak 102).

Was 2023 a good or bad year for Boise's air?

Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 3rd cleanest by days above AQI 100. 2023's median of 51 is below the area's typical annual median of 54.

Boise month by month in 2023

Boise air quality month by month, 2023 (Boise City, ID, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
January3156070PM2.5
February2853072PM2.5
Marchcleanest3140058O3
April3045090O3
May31491101O3
June3049074O3
Julyworst31561102O3
August3154098O3
September3047072O3
October31391120PM2.5
November3056088PM2.5
December3159074PM2.5

How 2023 compares

Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 3rd cleanest by days above AQI 100.

2023'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.