Air Quality in Nampa, Idaho — Live
Live readings from PurpleAir sensors across Nampa — with free alerts when winter inversions or harvest smoke move in.
AQI 41 from 4 PurpleAir sensors · Trending up · data from PurpleAir
As of , the air quality in Nampa, Idaho is AQI 41 — Good and rising — with PM2.5 at 7.4 µg/m³, the median of 4 live PurpleAir sensors reading 23 to 42. 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 Nampa: weeds pollen is the strongest of the three at a 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 Nampa and Caldwell, Meridian, Middleton, Kuna. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Nampa
The sensors Canairy reads in Nampa agree right now — all 4 sit in the Good band, a 19-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 2.1 mi WNW | 40 | Good |
| 2.1 mi WNW | 23 | Good |
| 3.8 mi S | 42 | Good |
| 7.0 mi ENE | 41 | Good |
Nampa's air is good most of the year — the Treasure Valley's pollution problems come less from freeways than from the farm country and winter weather that surround it. Two stretches of the year are different: cold winter nights, when the valley's own shape traps exhaust and wood smoke close to the ground, and harvest season, when Canyon County's fields get cleared with permitted, real crop-residue burning that fills the air with smoke you can actually see and smell.
What Canairy does for Nampa
A clear verdict
Not just a number — a plain-English call for Nampa: 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 Nampa or across the country, on one screen.
What the air in Nampa is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 44 | Good | ozone |
| Tomorrow | — | Good | ozone |
| Thursday | — | Good | ozone |
| Friday | — | Good | ozone |
| Saturday | — | Good | ozone |
Forecast from EPA AirNow for the Boise reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
The Treasure Valley traps its own air in winter
Nampa sits at about 2,474 feet elevation in the Treasure Valley, roughly 20 miles west of Boise, in a basin framed by the Boise foothills to the north and the high desert of the Owyhee uplands to the south. On cold, still nights — common in an Idaho winter — a layer of warmer air settles over the valley like a lid, trapping the cooler air, and everything the valley's cars, wood stoves, and farm equipment put into the air stays low instead of clearing out.
That mechanism was serious enough for decades that neighboring Ada County (Boise) still carries federal 'maintenance area' status from the EPA: a carbon monoxide nonattainment designation redesignated to maintenance in 2002, and a PM-10 particulate designation redesignated to maintenance in 2003 — both textbook results of winter inversions holding vehicle exhaust and fine dust close to the ground. Canyon County, where Nampa sits, shares the same valley floor and the same trapped air; an inversion doesn't stop at a county line.
Harvest season means real, permitted smoke over the fields
Canyon County is one of Idaho's most productive farm counties, and once crops like mint, onions, sugar beets, and corn are harvested, growers across the valley clear the stubble with crop-residue burning — a real practice regulated and tracked through Idaho DEQ's crop residue and spot-and-bale burn permit program, with rules meant to keep smoke away from schools, hospitals, and other sensitive sites nearby.
This isn't a hypothetical: DEQ actively manages burn days around the valley's weather, and outdoor burning across Canyon County (along with Ada and ten other Idaho counties) has been prohibited outright during active air quality advisories. In a typical year the heaviest agricultural burning runs from late summer into fall, and on top of it, haze can drift in from wildfires burning elsewhere in the Northwest.
What actually helps on a bad-air day in Nampa
On a winter inversion morning, checking the forecast matters more than checking the sky — the coldest, stillest mornings are often the worst even under clear blue skies, because the pollution is trapped low and fine rather than visible as haze. Closing up the house before the air turns and running a purifier indoors beats waiting until you can smell smoke or exhaust, since the small particles that build up during an inversion do their damage long before you'd notice anything by eye or nose.
Canairy reads the PurpleAir sensors placed around Nampa and Canyon County instead of leaning on one distant monitor, because a single valley-wide number hides real differences — the air near a field mid-burn can be very different from the air downtown at the same hour. Set a threshold once, and Canairy tells you when it's crossed, in either direction.
Nampa air quality FAQ
What is the air quality in Nampa right now?
As of September 15, 2026 at 5:10 AM PDT, the air quality in Nampa, Idaho is AQI 41 — Good — with PM2.5 at 7.4 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Nampa's air get worse in winter?
Nampa sits in the Treasure Valley, a basin ringed by higher ground that traps cold air close to the surface on calm winter nights. That trapped layer holds vehicle exhaust, wood-stove smoke, and fine dust near the ground instead of letting it disperse — the same inversion pattern that gave neighboring Ada County a long federal history of carbon monoxide and PM-10 maintenance-area status.
Why does it smell like smoke around Nampa during harvest season?
Canyon County farmers burn crop residue from fields after harvest, a permitted and DEQ-regulated practice used to clear stubble from crops like mint, onions, and sugar beets. Burn days are approved around the valley's weather and restricted near schools and hospitals, but on approved days the smoke is real and can affect neighborhoods well outside the fields themselves.
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 4 curated PurpleAir sensors Canairy tracks in and around Nampa, 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
Go deeper
Air quality near Nampa
We watch Nampa's air. You live your life.
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