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.

Live Knoxville AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Knoxville and Farragut, Oak Ridge, Maryville, Sevierville.

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.

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.

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?

This page shows the current AQI for Knoxville, 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 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 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 Knoxville data come from?

Readings come from PurpleAir's network of laser particle sensors across Knoxville 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.

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.