Metro area air quality · 2025
Knoxville, TN
Median AQI 48 (Good). 56.4% of monitored days rated Good across this metro's EPA monitoring network.
- 48
- Median AQI
- 56.4%
- Good-air days
- 1
- Unhealthy days
- 19%
- Cleaner than US metros
Knoxville, TN posted a 2025 median AQI of 48 (Good) with 56.4% Good days
According to the U.S. EPA Air Quality System, the Knoxville, TN CBSA recorded a median AQI of 48 across 365 monitored days in 2025, with 56.4% rated Good and 1 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Knoxville, TN CBSA's 56.4% Good-day share places it cleaner than 19% of US metros in 2025.
- Closest median-AQI peer
- Baltimore-Columbia-Towson, MD (58.1% Good, median AQI 48) is the closest nationwide median-AQI peer to Knoxville, TN.
- 2020–2025 Good-day shift
- Knoxville, TN's Good-day share moved -1.1 points from 2020 to 2025 (median AQI +1).
- Median AQI
- Median AQI: 48
Aggregated from EPA Air Quality System (2025), 365 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 48 with 56.4% of 365 monitored days in the Good band.
- 48
- median AQI · Good
- 56.4%
- days rated Good
- 19%
- cleaner than US metros
- 156
- worst single reading
1 day reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Knoxville, TN metro's Good-day share rose from 45.5% to 56.6% between the 2024 and 2025 EPA annual releases, a change of +11.1 percentage points.
- Knoxville, TN metro's peak single-day AQI rose from 105 to 156 between the 2024 and 2025 EPA annual releases, a change of +51 points.
- Knoxville, TN metro's median AQI fell from 52 to 48 between the 2024 and 2025 EPA annual releases, a change of -4 points.
- Knoxville, TN metro's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Insights: Knoxville, TN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 48 over 365 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 206 Good days (56%), 157 Moderate (43%), 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 16.9 clean-air days per 30-day window across the reporting year.
Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -1.1 points and the median AQI moved +1 points, which classifies the multi-year trajectory as stable. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Baltimore-Columbia-Towson, MD (58.1% good, AQI 48); Boulder, CO (58.4% good, AQI 48); Columbus, GA-AL (53.4% good, AQI 48).
Air Quality Summary
Median AQI
48
Good
Good Days
56.4%
206 of 365 days
Max AQI
156
Unhealthy
Health Grade
Moderate
90th pct: 61
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
206
56%
Moderate
157
43%
USG
1
0%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Knoxville, TN metro area's air quality is rated Moderate based on 56.4% 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
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 | Max AQI |
|---|---|---|---|---|---|
| 2020 | 211 | 155 | 0 | 47 | 97 |
| 2021 | 146 | 213 | 0 | 53 | 150 |
| 2022 | 167 | 196 | 1 | 52 | 162 |
| 2023 | 144 | 213 | 0 | 53 | 149 |
| 2024 | 166 | 199 | 0 | 52 | 105 |
| 2025 | 206 | 157 | 1 | 48 | 156 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Knoxville, TN (48).
Baltimore-Columbia-Towson, MD
Median AQI 48 · 58.1% Good-day share
Boulder, CO
Median AQI 48 · 58.4% Good-day share
Columbus, GA-AL
Median AQI 48 · 53.4% Good-day share
Durango, CO
Median AQI 48 · 60.8% Good-day share
Greenville-Anderson-Mauldin, SC
Median AQI 48 · 55.3% Good-day share
Lake City, FL
Median AQI 48 · 57.3% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Knoxville, TN's 1 (independent of median AQI).
Ann Arbor, MI
1 unhealthy-or-worse days · median AQI 41
Bangor, ME
1 unhealthy-or-worse days · median AQI 33
Baraboo, WI
1 unhealthy-or-worse days · median AQI 35
Bartlesville, OK
1 unhealthy-or-worse days · median AQI 44
Beaumont-Port Arthur, TX
1 unhealthy-or-worse days · median AQI 52
Beaver Dam, WI
1 unhealthy-or-worse days · median AQI 40
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? ▼
How many unhealthy air days does Knoxville, TN have? ▼
Is air quality in Knoxville, TN getting better or worse? ▼
What does AQI 48 mean for health? ▼
What is the 90th percentile AQI for Knoxville, TN? ▼
How does Knoxville, TN compare to other metro areas? ▼
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
Share this annual record
Send the source-year summary or download its ready-to-use data card.
Every figure on PlainAirData 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.