Boise, ID Air Quality Index (AQI)
During a smoke episode the air over Boise can shift hour to hour. This page uses EPA's NowCast — the same weighting AirNow uses — so the "current" number reflects fast changes instead of a stale 24-hour average. Peak smoke risk here runs mid-summer into fall, when Western wildfires and long-range plumes settle into the valleys.
About air quality in Boise
Boise is the 1st most populous of the 3 Idaho cities we track, with a population of about 235,684, in Ada County.
Smoke risk here concentrates in mid-July through September, driven by regional fires plus smoke drawn down from British Columbia, which can hold for days once it settles into a valley. Outside that window an elevated reading in Boise is more likely to be local — traffic, dust, or a temperature inversion holding everyday pollution near the ground — than wildfire smoke, and the dominant pollutant shown above is what tells the two apart.
How local is this reading? The AQI above is reported for a monitoring area, not for a street address. The nearest city we track is Idaho Falls, ID, about 209 miles away — far enough that conditions between the two can differ substantially, and worth checking both during an active plume.
Today & tomorrow
What each level means
| AQI | Level | What to do |
|---|---|---|
| 0–50 | Good | A great day to be active outside. |
| 51–100 | Moderate | Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors and watch for symptoms. |
| 101–150 | Unhealthy for Sensitive Groups | Sensitive groups should reduce prolonged or heavy exertion outdoors, take more breaks, and reschedule strenuous activities. |
| 151–200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should move activities indoors or reschedule. |
| 201–300 | Very Unhealthy | Everyone should avoid prolonged or heavy exertion and move activities indoors; sensitive groups should stay indoors and keep activity low. |
| 301–500 | Hazardous | Everyone should avoid all physical activity outdoors; stay indoors with clean air and keep activity low. |
Guidance paraphrased from EPA. Not medical advice — see disclaimer.
Nearby cities
All Idaho cities · Smoke & your health · Can I go outside?
Boise air quality FAQ
What is the air quality in Boise right now?
The live AQI for Boise, ID is shown at the top of this page, sourced from AirNow (U.S. EPA) and computed with the 2024 EPA standard, with the observation time and source labeled.
Is it safe to go outside in Boise today?
It depends on the current AQI and whether you're in a sensitive group. At AQI 101–150 sensitive groups should cut back on prolonged outdoor exertion; at 151+ everyone should. Use our "Can I go outside?" tool for tailored guidance.
Why does Boise's AQI here match AirNow?
Because AirNow is our display truth for US monitors — we show its reported number, never a self-computed value that disagrees with it for the same monitor.
When is wildfire smoke worst in Idaho?
In the West, smoke risk peaks mid-summer through fall during active fire season and can linger in valleys.