Air Quality in Boise, Idaho — Live

Live readings from PurpleAir sensors across Boise — with free alerts the moment the air turns.

Live Boise AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Boise and Meridian, Garden City, Eagle, Nampa, Kuna.

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.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

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

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.

What is the air quality in Boise right now?

This page shows the current AQI for Boise, calculated from PurpleAir sensors across the city and updated continuously. Readings can differ noticeably between the foothills and the valley floor during an inversion, when the trapped layer sits low, so it is worth finding the sensor closest to you on the map below rather than relying on one citywide figure.

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 AQI level is unhealthy?

Under the US EPA scale, AQI 0–50 is Good and 51–100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups — kids, older adults, and people with asthma or heart conditions — and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.