Air Quality in Knoxville, Tennessee — Live
Live readings from PurpleAir sensors across Knoxville — with free alerts the moment summer ozone or valley haze turns the air unhealthy.
AQI 61 from 4 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Knoxville, Tennessee is AQI 61 — Moderate and holding steady — with PM2.5 at 14.5 µg/m³, the median of 4 live PurpleAir sensors reading 53 to 66. 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 Knoxville: 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 Knoxville and Farragut, Oak Ridge, Maryville, Sevierville. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Knoxville
The sensors Canairy reads in Knoxville agree right now — all 4 sit in the Moderate band, a 13-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.2 mi NE | 53 | Moderate |
| 5.4 mi SW | 62 | Moderate |
| 10.2 mi E | 66 | Moderate |
| 13.6 mi NE | 61 | Moderate |
Most of the year, Knoxville's air is unremarkable in the best way. The trouble shows up on hot, still summer afternoons, when the same valley that gives East Tennessee its scenery also traps heat, humidity, and car exhaust long enough for ground-level ozone to build past healthy levels — the reason Knox County spent 2012 to 2015 under an EPA nonattainment designation and still operates under a federal ozone maintenance plan today.
What Canairy does for Knoxville
A clear verdict
Not just a number — a plain-English call for Knoxville: 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 Knoxville or across the country, on one screen.
Knoxville's ozone problem is really a valley problem
Knoxville sits in the Great Appalachian Valley, boxed in by the Cumberland Plateau to the west and the Great Smoky Mountains roughly 20 miles to the southeast. That ridge-and-valley terrain limits the wind that would otherwise clear the air, and on hot, sunny days from about May through September, sunlight cooks vehicle and industrial exhaust into ground-level ozone that has nowhere to go. The EPA designated the Knoxville metro area nonattainment for the 2008 ozone standard in July 2012; after several cleaner summers the region was redesignated to attainment with a maintenance plan in August 2015, and it remains in that maintenance status today, meaning regulators still watch it closely on the hottest afternoons.
Ozone here doesn't build overnight — it peaks in mid- to late afternoon after hours of sun, then usually fades by evening. That daily rhythm is why a single morning reading tells you very little about whether it's a good day for an afternoon run or a school recess outside.
TVA's coal plants left a mark on the region's air and its views
For decades, sulfur dioxide from TVA's coal-fired power plants was the dominant source of haze across East Tennessee. The Bull Run Fossil Plant sat about 20 miles northwest of Knoxville in Claxton and ran from 1967 until TVA shut it down for good on December 1, 2023. The Kingston Fossil Plant, about 40 miles west in Roane County, is still operating — it's also the site of the December 2008 coal ash spill, when a ruptured impoundment released roughly 1.1 billion gallons of coal ash slurry into the Emory and Clinch rivers, one of the largest industrial spills in U.S. history.
That sulfate pollution didn't stay local. The National Park Service says average visibility in the Smokies has dropped about 40 percent in winter and 80 percent in summer since 1948, and ozone on the park's ridgetops can run up to twice as high as in nearby Knoxville itself, because the same mountains that box in the valley also trap and concentrate pollution blown in from the region's power plants, factories, and highways. Knoxville's air and the haze over the national park next door are, in a real sense, the same airshed.
What actually helps on a high-ozone day
Ozone is worst in direct sun during the hottest part of the day, so shifting an outdoor workout, a kids' practice, or lawn mowing to the morning or evening avoids most of the exposure without avoiding the outdoors altogether. Afternoon thunderstorms, common in an East Tennessee summer, also tend to scrub ozone out of the air for a few hours afterward.
Because ozone forms locally from traffic and industry rather than drifting in from a single distant source, levels can vary block to block along a highway corridor like I-40 or I-75 versus a shaded neighborhood a mile away. That's why Canairy reads the network of sensors across Knoxville instead of a single monitor for the whole metro — the reading you see comes from sensors near the places you've actually saved.
Knoxville air quality FAQ
What is the air quality in Knoxville right now?
As of September 14, 2026 at 9:58 AM EDT, the air quality in Knoxville, Tennessee is AQI 61 — Moderate — with PM2.5 at 14.5 µg/m³, the median of 4 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why does Knoxville struggle with ozone in the summer?
Knoxville sits in a valley boxed in by the Cumberland Plateau and the Great Smoky Mountains, which limits the wind that would otherwise clear the air. On hot, sunny days from roughly May through September, sunlight converts vehicle and industrial exhaust into ground-level ozone. The EPA designated the metro area nonattainment for ozone in 2012 and returned it to attainment with a maintenance plan in 2015 — a status it still carries today.
Did TVA's coal plants affect Knoxville's air?
Yes. The Bull Run Fossil Plant, about 20 miles northwest of Knoxville, ran from 1967 until it was retired on December 1, 2023, and the Kingston Fossil Plant 40 miles west is still operating — it's also the site of the 2008 coal ash spill, one of the largest industrial spills in U.S. history. Sulfate pollution from plants like these has long been the main driver of the haze that has cut visibility in the nearby Great Smoky Mountains by 40 to 80 percent since 1948.
Does wildfire smoke ever reach Knoxville?
It's occasional rather than an annual pattern. The most notable case was the Chimney Tops 2 Fire near Gatlinburg in November 2016, which pushed unhealthy air quality into Sevier County roughly 35 miles southeast of Knoxville. Smoke from fires in the Smokies or nearby national forests can drift into the valley depending on wind direction, but it isn't the recurring seasonal story here the way summer ozone is.
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 Knoxville, 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 Knoxville
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