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
Knoxville, TN lands in the lower Good-day tercile (56.4% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, among the more polluted US metros, with a median AQI of 48 and 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.
Knoxville, TN lands in the lower Good-day tercile (56.4% Good), a thinner clean-air share than most CBSA peers here. Signature read: 56.4% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 48 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 206 Good (56%), 157 Moderate (43%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61; the highest single-day reading hit 156 (Unhealthy).
Across 2020–2025, Good-day share shifted -1.1 points and median AQI moved +1 (stable). The annual record contains 1 day at Unhealthy or worse. 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. Highest Good-day share: 2020 (57.7%, 211 of 366 monitored 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
Frequently Asked Questions
How many unhealthy air days does Knoxville, TN have? ▼
What is the air quality in the Knoxville, TN metro area? ▼
Is air quality in Knoxville, TN getting better or worse? ▼
What does AQI 48 mean for health? ▼
How does Knoxville, TN compare to other metro areas? ▼
What is the 90th percentile AQI for Knoxville, TN? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Knoxville, TN, 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, Knoxville, TN · 2020–2025