Air Quality in Chattanooga, Tennessee — Live
Live readings from PurpleAir sensors across Chattanooga — with free alerts when summer ozone builds up in the valley.
AQI 60 from 3 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Chattanooga, Tennessee is AQI 60 — Moderate and holding steady — with PM2.5 at 13.8 µg/m³, the median of 3 live PurpleAir sensors reading 56 to 61. Canairy's verdict: Mostly clear.
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 Chattanooga: weeds pollen is the strongest of the three at a moderate 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 Chattanooga and East Ridge, Red Bank, Signal Mountain, Hixson. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Chattanooga
The sensors Canairy reads in Chattanooga agree right now — all 3 sit in the Moderate band, a 5-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 0.7 mi ESE | 56 | Moderate |
| 8.5 mi NNW | 60 | Moderate |
| 8.7 mi NE | 61 | Moderate |
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.
What Canairy does for Chattanooga
A clear verdict
Not just a number — a plain-English call for Chattanooga: 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 Chattanooga or across the country, on one screen.
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?
As of September 14, 2026 at 6:38 PM EDT, the air quality in Chattanooga, Tennessee is AQI 60 — Moderate — with PM2.5 at 13.8 µg/m³, the median of 3 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
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 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 3 curated PurpleAir sensors Canairy tracks in and around Chattanooga, 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 Chattanooga
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