Metro area air quality · 2025

Knoxville, TN

Median AQI 49 (Good). 55.3% of monitored days rated Good across this metro's EPA monitoring network.

49
Median AQI
55.3%
Good-air days
1
Unhealthy days
18%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 273 monitored days. EPA AQS →

The verdict

The Knoxville, TN metro runs good on the EPA scale, among the more polluted US metros, a median AQI of 49 with 55.3% of 273 monitored days in the Good band.

49
median AQI · Good
55.3%
days rated Good
18%
cleaner than US metros
156
worst single reading

1 day reached Unhealthy or worse across the metro's monitors in 2025.

Insights: Knoxville, TN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 49 over 273 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 151 Good days (55%), 120 Moderate (44%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 156 (Unhealthy). Metro residents averaged roughly 16.6 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -60 and the median AQI moved +2 points, which classifies the multi-year trajectory as stable. The metro recorded 1 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Colorado Springs, CO (58.2% good, AQI 49); Farmington, NM (58.2% good, AQI 49); Greenville-Anderson-Mauldin, SC (53.5% good, AQI 49).

Air Quality Summary

Median AQI

49

Good

Good Days

55.3%

151 of 273 days

Max AQI

156

Unhealthy

Health Grade

Moderate

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 273 monitored days across EPA AQI categories.

Good

151

55%

Moderate

120

44%

USG

1

0%

Unhealthy

1

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Knoxville, TN metro area's air quality is rated Moderate based on 55.3% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 1 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 156. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Knoxville, TN metro compare?

How Knoxville, TN compares

Good-day share worse than US avg
Knoxville, TN 55.3%
Colorado Springs, CO 58.2%
US average 71.3%
Median AQI worse than US avg
Knoxville, TN 49
Colorado Springs, CO 49
US average 41
Unhealthy days / yr about average
Knoxville, TN 1
Colorado Springs, CO 0
US average 1

5-Year Air Quality Trend

Air quality is stable in the Knoxville, TN metro. Best year: 2020 (211 good days).

Year Good Moderate Unhealthy Median AQI
2020 211 155 0 47
2021 146 213 0 53
2022 167 196 1 52
2023 144 213 0 53
2024 166 199 0 52
2025 151 120 1 49

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Knoxville, TN.

Colorado Springs, CO

AQI 49 · 58.2% good

49

Farmington, NM

AQI 49 · 58.2% good

49

Greenville-Anderson-Mauldin, SC

AQI 49 · 53.5% good

49

Hot Springs, AR

AQI 49 · 52.8% good

49

Kansas City, MO-KS

AQI 49 · 50.8% good

49

Kingsville, TX

AQI 49 · 51.7% good

49

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Knoxville, TN metro area? ▼
The Knoxville, TN metro area has a median Air Quality Index (AQI) of 49, rated "Good." 55.3% of monitored days (151 out of 273) had good air quality in 2025.
How many unhealthy air days does Knoxville, TN have? ▼
In 2025, the Knoxville, TN metro area recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 156.
Is air quality in Knoxville, TN getting better or worse? ▼
Air quality in the Knoxville, TN metro is stable based on 5-year trends (2020-2025). Best year: 2020 with 211 good days. Worst year: 2023 with 144 good days.
What does AQI 49 mean for health? ▼
An AQI of 49 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Knoxville, TN? ▼
The 90th percentile AQI for the Knoxville, TN metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 156 (Unhealthy).
How does Knoxville, TN compare to other metro areas? ▼
The Knoxville, TN metro has 55.3% good air days. Similar metros: Colorado Springs, CO (58.2% good), Farmington, NM (58.2% good), Greenville-Anderson-Mauldin, SC (53.5% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. See our methodology for how AQI, median, and coverage figures are computed.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.