Air Quality in Butte, Montana — Live

Live readings from PurpleAir sensors across Butte — with free alerts when mine dust or winter smoke moves in.

Live Butte AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Butte and Walkerville, Anaconda, Whitehall, Deer Lodge.

Butte's air is shaped more by what's underfoot than what's on fire. A century of copper mining under the Anaconda Company left the city with a dust problem serious enough that the EPA once classified it as a PM10 nonattainment area, and the Continental Pit mine still runs today just north of downtown. Add cold winter nights that trap wood smoke in the valley, plus a few smoky weeks most summers when western Montana's wildfire season kicks up, and you get a place where the air is fine most days but has real, specific reasons when it isn't.

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.

Butte's dust problem didn't end when the mines closed

A century of copper mining and smelting under the Anaconda Company left Butte with enough airborne particulate that the EPA designated the city a moderate nonattainment area for PM10 on March 15, 1991. For decades afterward, monitors at the Greeley School site on the north side of town tracked whether cleanup and dust-control work were actually paying off.

They were: using five years of data from 2014 through 2018, Montana's Department of Environmental Quality petitioned the EPA, and on July 26, 2021 Butte was reclassified out of nonattainment and into a maintenance plan. That's real, measurable progress - but it's also why Butte-Silver Bow still runs continuous PM10 monitoring at Greeley today rather than treating the issue as closed history.

The Continental Pit still runs, and Greeley feels it

Montana Resources' Continental Pit - an active open-pit copper and molybdenum mine - is the only mining operation still working the ground at Butte, and it sits close enough to the Greeley neighborhood that only a two-lane road separates the pit from roughly 700 homes. Fugitive dust blowing off the mine is a present-day concern for those residents, not a relic of the smelter era.

In late 2023, the Greeley Neighborhood Community Development Corporation surveyed residents with grant funding from the Center for Health, Environment & Justice, and pinpointed the specific streets where people worried most about dust drifting over from the pit. Montana Resources responded by starting monthly dustfall sampling that August at Pine Street, Walnut Street, and the Greeley School site, and told the Butte-Silver Bow Board of Health it would help fund research into the health effects of mine dust.

Winter adds wood smoke to a valley that already holds its air

Butte sits at almost 5,800 feet in a mountain-ringed valley on the Continental Divide, and on cold, calm nights that terrain lets cool air pool near the ground instead of mixing out - a classic winter inversion. Butte-Silver Bow's own air quality program warns that just 20 old, non-EPA-certified wood stoves can put more than a ton of fine particle pollution into a neighborhood over the cold months, which is why the county has a standing Air Quality Control Ordinance covering residential wood heaters.

Summer brings a different, more borrowed problem: wildfire smoke. Butte isn't usually ground zero for a fire the way some Montana towns are, but it shares the same regional smoke seasons - 2017's stretch of haze across western Montana, remembered locally as the state's worst 'summer of smoke,' settled over the Butte area for weeks even though the largest fires were burning near Missoula and the Bitterroot. Montana DEQ's statewide smoke forecasts exist because a clear Butte morning can turn hazy by afternoon from a fire burning nowhere near Silver Bow County.

Butte air quality FAQ

What is the air quality in Butte right now?

This page shows the current AQI for Butte, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood.

Why does the Greeley neighborhood worry about dust from the mine?

Montana Resources' Continental Pit, an active copper and molybdenum mine, sits just across a two-lane road from roughly 700 homes in Greeley. A 2023 resident survey identified specific streets most concerned about fugitive dust, and Montana Resources now runs monthly dustfall sampling at Pine Street, Walnut Street, and Greeley School to track it.

Does Butte still have a mining-related air pollution problem?

It's much improved but still monitored. The EPA designated Butte a PM10 nonattainment area in 1991 because of dust tied to a century of mining and smelting. Cleanup progress was strong enough that the city was reclassified to attainment under a maintenance plan in 2021, and continuous PM10 monitoring continues at the Greeley School site today.

Why does Butte's air get worse on cold winter nights?

Butte sits nearly a mile high in a mountain-ringed valley, and on calm winter nights a temperature inversion traps cold air - and wood smoke from home stoves and fireplaces - close to the ground instead of letting it mix away. Butte-Silver Bow's air quality program notes that just 20 old, uncertified wood stoves can add more than a ton of fine particle pollution to a neighborhood over the cold season.

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.

Where does Canairy's Butte data come from?

Readings come from PurpleAir's network of laser particle sensors across Butte and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

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