Median AQI
42
Good
Tennessee · County air quality · 2025
Anderson County, Tennessee
Median AQI 42 (Good). 91.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 42
- Median AQI
- 91.0%
- Good-air days
- 0
- Unhealthy days
- 78%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Anderson County's air is good on balance, cleaner than most US counties, a median AQI of 42 with 91.0% of 122 monitored days in the Good band, driven mainly by Ozone.
- 42
- median AQI · Good
- 91.0%
- days rated Good
- Ozone
- main pollutant
- 78%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 105.
Data updated July 2026
- Good · 111 d · 91.0%
- Moderate · 10 d · 8.2%
- USG · 1 d · 0.8%
How did Anderson County's air break down in 2025?
Across 122 monitored days, 111 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 105 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 122 days monitored. Median AQI: 42 (Good).
Insights: Anderson County, Tennessee. EPA monitors recorded a median Air Quality Index of 42 across 122 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 111 (91%) fell in the Good band (AQI 0–50), 10 (8%) registered Moderate readings, and 1 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 50, while the worst single-day peak hit 105 (USG). Residents averaged about 27.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (122 days). Across the 2020–2025 trend window, good days shifted by -127 and the median AQI moved +7 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 105, usg but never Unhealthy. Nearby counties show comparable readings: Blount (69.6% good, AQI 46); Claiborne (96.3% good, AQI 36); Davidson (51.8% good, AQI 50); DeKalb (95.4% good, AQI 35); Dyer (79.4% good, AQI 34); Hamilton (64.1% good, AQI 45).
Air Quality Summary
Good Days
91.0%
111 of 122 monitored days
16.0pp vs 75% target
Max AQI Recorded
105
USG
Health Grade
Excellent
90th-pct AQI 50
Anderson County, Good days share 91.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Anderson County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 122 monitored days across EPA AQI categories.
Good
111
91%
Moderate
10
8%
USG
1
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Anderson County.
- Ozone · 122 days · 100.0%
Health Impact Assessment
Excellent
Anderson County's air quality is rated Excellent based on 91.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 91.0% of monitored days in 2025, with a median AQI of 42. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 122 of 122 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Anderson County. Best year: 2020 (238 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 238 | 7 | 0 | 0 | 35 | 64 |
| 2021 | 219 | 16 | 0 | 0 | 38 | 87 |
| 2022 | 228 | 17 | 0 | 0 | 39 | 80 |
| 2023 | 212 | 24 | 1 | 0 | 41 | 105 |
| 2024 | 221 | 22 | 0 | 0 | 41 | 100 |
| 2025 | 111 | 10 | 1 | 0 | 42 | 105 |
How does Anderson County compare?
How Anderson County compares
Good-day share better than US avg
Anderson County 91.0%
Blount County, Tennessee 69.6%
US average 76.5%
Median AQI worse than US avg
Anderson County 42
Blount County, Tennessee 46
US average 38
Unhealthy days / yr about average
Anderson County 0
Blount County, Tennessee 0
US average 0
Other Counties in Tennessee
Air quality comparison for nearby counties in Tennessee.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Anderson County.
Adams County, Pennsylvania
AQI 42 · 73.8% good
Andrew County, Missouri
AQI 42 · 84.3% good
Armstrong County, Pennsylvania
AQI 42 · 68.1% good
Baldwin County, Alabama
AQI 42 · 72.2% good
Belmont County, Ohio
AQI 42 · 63.0% good
Buncombe County, North Carolina
AQI 42 · 71.4% good
What Anderson County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 42 means for exposure. Health guidance
- See how Anderson County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Anderson County with its Tennessee neighbours before drawing a conclusion about the region. All of Tennessee
Based on 122 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Anderson County, Tennessee? ▼
Anderson County has a median Air Quality Index (AQI) of 42, rated "Good." 91.0% of monitored days (111 out of 122) had good air quality in 2025.
What is the main pollutant in Anderson County? ▼
The primary pollutant in Anderson County is Ozone (O3), which was the main AQI driver on 122 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Anderson County have? ▼
In 2025, Anderson County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 105.
Is the air quality in Anderson County getting better or worse? ▼
Air quality in Anderson County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 238 good days. Worst year: 2025 with 111 good days.
What does AQI 42 mean for health? ▼
Anderson County's median AQI of 42 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Anderson County compare to other counties in Tennessee? ▼
Anderson County has 91.0% good air days. Nearby counties in Tennessee: Blount (69.6% good), Claiborne (96.3% good), Davidson (51.8% good), DeKalb (95.4% good), Dyer (79.4% good), Hamilton (64.1% good).
What is the 90th percentile AQI in Anderson County? ▼
The 90th percentile AQI for Anderson County is 50, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 105 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
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.