Air Quality in Boise, Idaho — Live
Live readings from PurpleAir sensors across Boise — with free alerts the moment the air turns.
AQI 24 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Boise, Idaho is AQI 24 — Good and falling — with PM2.5 at 4.4 µg/m³, the median of 5 live PurpleAir sensors reading 0 to 29. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Boise: weeds pollen is the strongest of the three at a very high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Boise and Meridian, Garden City, Eagle, Nampa, Kuna. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Boise
The sensors Canairy reads in Boise agree right now — all 5 sit in the Good band, a 29-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.4 mi S | 26 | Good |
| 2.4 mi W | 23 | Good |
| 4.3 mi SE | 0 | Good |
| 5.9 mi SSE | 29 | Good |
| 10.0 mi NW | 13 | Good |
Idaho's Department of Environmental Quality sums the Treasure Valley up in one line: inversions in the winter, ozone and wildfire pollution in the summer. Boise sits at about 2,704 feet on the floor of that valley, the largest and most heavily populated urban area in the state, and the same topography that makes it a pleasant place to live also makes it good at holding on to whatever ends up in the air. Northern Ada County was designated nonattainment for carbon monoxide and coarse particles back in 1990 and worked its way back to attainment with maintenance plans in 2002 and 2003, but the seasonal pattern underneath that has not changed.
What Canairy does for Boise
A clear verdict
Not just a number — a plain-English call for Boise: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Boise or across the country, on one screen.
Inversion season runs late November to mid-February
During inversion season a layer of warm air settles over the valley and traps the cooler, denser air underneath it, and everything in that lower layer — wood smoke, car exhaust, industrial emissions — stays put and builds up. Boise State's Resilience Institute puts the season at late November through mid-February across southwest Idaho and southeast Oregon. The pollutants that historically caused the most trouble here came from ordinary domestic and road sources: DEQ attributes Northern Ada County's coarse particle problem to fugitive road dust, agriculture and residential wood heating, and its carbon monoxide problem to vehicles and area sources.
Boise's response is written into local ordinance, and it is worth knowing the two numbers. When the AQI reaches 60 or above, open and outdoor burning is prohibited but fireplaces and woodstoves are still allowed. When it reaches 74 or above, all wood burning stops — open burning, fireplaces and woodstoves alike. Those thresholds sit well below the levels most people think of as an emergency, which is a fair signal of how quickly a stagnant valley can fill.
Most of Boise's smoke starts somewhere else
The Treasure Valley sits downwind of a very large amount of country that burns. On 22 July 2026 Idaho DEQ issued an air quality advisory for Ada, Canyon, Gem, Payette and Washington counties as smoke from wildfires in central Oregon and Washington funnelled into western Idaho. The agency's regional coordinator, Mike Toole, put it plainly: "We are right now in the red. It's not good out there." By 27 July the advisory had grown to cover 33 Idaho counties, with all burning prohibited — campfires, firepits, residential burns, weed control and prescribed fire. Barbecue grills were still allowed, since they do not count as outdoor burning.
Fires close to home are less frequent but they are not rare. The Valley Fire started around 4:15 on the morning of 4 October 2024 about a mile east of Boise, on the north side of Highway 21, after a broken cross arm on an Idaho Power pole let an energised line touch the ground. It burned 9,904 acres in the foothills, closed Highway 21, put heavy smoke over the city and closed East Junior High and Dallas Harris Elementary. No homes were lost.
Field burning is regulated, and you can find out when it is happening
Idaho does allow growers to burn crop residue, but under a permit system run by DEQ rather than at will. A permit is required for any burn larger than an acre a day, billed at $2 an acre, and the grower has to have direct approval from DEQ field staff before ignition. Fields must sit on a public list for at least 24 hours before they can be considered for burning, and DEQ is required to keep approved smoke away from public schools while in session, hospitals and residential care facilities for children, the elderly and the infirm.
That means agricultural smoke around the Treasure Valley is not random — there is a published burn decision each day and a map showing what was approved. If your sensor spikes on an otherwise clear afternoon in the shoulder seasons and there is no fire in the news, a nearby approved burn is worth ruling out.
Boise air quality FAQ
What is the air quality in Boise right now?
As of September 10, 2026 at 5:11 AM PDT, the air quality in Boise, Idaho is AQI 24 — Good — with PM2.5 at 4.4 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in Boise today?
In summer, the usual answer is wildfire smoke drifting in from outside Idaho. In late July 2026 the source was fires burning in central Oregon and Washington, which pushed the Treasure Valley into the red and prompted DEQ advisories that eventually covered 33 counties with all burning prohibited. Fires close to the city do happen — the Valley Fire burned 9,904 acres in the foothills a mile east of Boise in October 2024 and put heavy smoke over town — but most smoke days here start hundreds of miles upwind. In winter, haze that looks like smoke is usually an inversion holding wood smoke and exhaust in the valley.
When can't I use my woodstove in Boise?
Boise's local ordinances tie it directly to the AQI. At 60 or above, open and outdoor burning is prohibited, though fireplaces and woodstoves are still permitted. At 74 or above, all wood burning is prohibited, including fireplaces and woodstoves. Those thresholds are checked against DEQ's reported air quality, and during a hard winter inversion the valley can cross them for days at a stretch.
When is Boise's air usually at its worst?
Two seasons, for two different reasons. Inversion season runs roughly late November to mid-February, when warm air caps the valley and holds wood smoke, vehicle exhaust and road dust near the ground. Then July through September brings wildfire smoke, mostly transported in from fires in Idaho, Oregon and Washington, sometimes for weeks at a time. Idaho DEQ describes the Treasure Valley's pattern as inversions in the winter and ozone and wildfire pollution in the summer.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Boise, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Boise
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