Air Quality in Chattanooga, Tennessee — Live

Live readings from PurpleAir sensors across Chattanooga — with free alerts when summer ozone builds up in the valley.

Live Chattanooga AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Chattanooga and East Ridge, Red Bank, Signal Mountain, Hixson.

Chattanooga's air is genuinely clean most of the year now, which would have stunned anyone living here in 1969, when federal health officials called it the dirtiest city in America. The valley and ridges that once trapped industrial smoke over downtown still shape the air today, mostly in the form of summer ozone rather than smoke — Hamilton County posts a Moderate or better AQI on most days, but hot, humid, stagnant afternoons from roughly May through September can push ozone into the range where sensitive groups should scale back outdoor exertion.

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.

Chattanooga was once America's dirtiest city

In 1969, the federal Department of Health, Education and Welfare declared Chattanooga the worst city in the nation for particulate air pollution — the culmination of decades of unregulated smoke from foundries, textile mills, coal-burning furnaces, and rail yards settling into the Tennessee River valley. Tuberculosis mortality in the city ran roughly three times the national average at the time, and Chattanooga was already ranked the third-worst city in the country for soot pollution back in 1961.

That 1969 designation became the turning point. Hamilton County voters approved a strict Air Pollution Control Ordinance that same year, and local industry spent more than $40 million retrofitting smokestacks and boilers. Every major source was in compliance by the October 14, 1972 deadline, and the city marked the achievement with a Clean Air Week. Chattanooga has met federal air quality standards continuously since 1989 — the same valley that once trapped the soot is why Canairy still pays close attention here on the days modern pollution tries to build up.

The valley and ridges still trap summer ozone

Downtown Chattanooga sits at only about 676 feet in elevation, low ground hemmed in by Walden's Ridge and Signal Mountain to the north and the Appalachian ridge-and-valley chain to the south and east, with Missionary Ridge cutting through the middle of the city itself. That bowl shape is what caused the historic soot problem, and on hot, windless summer days it still produces temperature inversions and stagnant air — conditions that let vehicle exhaust and industrial emissions cook into ground-level ozone instead of blowing through.

The American Lung Association's 2026 State of the Air report gave Hamilton County a C grade for ozone, with the Chattanooga-Cleveland-Dalton metro area ranked 110th worst in the country for ozone pollution, slightly worse than the year before. The Chattanooga-Hamilton County Air Pollution Control Bureau runs a seasonal brush-burning ban through September 30 and asks drivers to hold off refueling until after 6 p.m. on the highest-ozone days, since gasoline vapors react faster with sunlight and heat.

What to actually do on a high-ozone day

Ozone builds through the afternoon as sun and heat do their work, so the worst hours on a hot, still summer day are typically mid-afternoon into early evening, not the morning. If you or your kids have asthma, it's worth moving a run or outdoor practice earlier in the day rather than judging by the sky, because ground-level ozone doesn't look like anything until it's already irritating your lungs.

Canairy reads the PurpleAir sensors scattered across the valley and up onto the surrounding ridges instead of relying on one official monitor, so the number you see reflects the neighborhood you actually saved — whether that's downtown, up on Signal Mountain, or out toward Hixson. Set a threshold once and we'll tell you when it's crossed, and when the air clears again.

Chattanooga air quality FAQ

What is the air quality in Chattanooga right now?

This page shows the current AQI for Chattanooga, 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, from downtown to Signal Mountain to East Ridge.

Why was Chattanooga once called the dirtiest city in America?

In 1969 the federal Department of Health, Education and Welfare named Chattanooga the worst city in the nation for particulate air pollution, the result of decades of unregulated smoke from foundries, textile mills, and coal furnaces settling into the Tennessee River valley. Hamilton County passed a tough Air Pollution Control Ordinance that same year, and by the October 1972 compliance deadline - at a cost of more than $40 million - every major industrial source in the city had cleaned up. Chattanooga has met federal air quality standards continuously since 1989.

Why does Chattanooga still get ozone alerts in summer?

The same ridges and valley bowl that once trapped industrial soot over downtown now trap heat, humidity, and vehicle exhaust on still summer afternoons, cooking it into ground-level ozone. Hamilton County earned a C grade for ozone in the American Lung Association's 2026 State of the Air report, and the county runs a seasonal brush-burning ban and asks drivers to fuel up after 6 p.m. on the highest-ozone days from spring through September.

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 Chattanooga data come from?

Readings come from PurpleAir's network of laser particle sensors across Chattanooga and surrounding Hamilton County 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.

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.