Median AQI
41
Good
Tennessee · County air quality · 2025
Loudon County, Tennessee
Median AQI 41 (Good). 81.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 81.8%
- Good-air days
- 0
- Unhealthy days
- 57%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Loudon County's air is good on balance, cleaner than the median US county, a median AQI of 41 with 81.8% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 41
- median AQI · Good
- 81.8%
- days rated Good
- PM2.5
- main pollutant
- 57%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 100.
Data updated July 2026
- Good · 148 d · 81.8%
- Moderate · 33 d · 18.2%
How did Loudon County's air break down in 2025?
Across 181 monitored days, 148 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 100 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 41 (Good).
Insights: Loudon County, Tennessee. EPA monitors recorded a median Air Quality Index of 41 across 181 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 148 (82%) fell in the Good band (AQI 0–50), 33 (18%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 55, while the worst single-day peak hit 100 (Moderate). Residents averaged about 24.5 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (110 days), Ozone (71 days). Across the 2020–2025 trend window, good days shifted by -151 and the median AQI moved +3 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 100, moderate but never Unhealthy. Nearby counties show comparable readings: Anderson (91.0% good, AQI 42); 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).
Air Quality Summary
Good Days
81.8%
148 of 181 monitored days
6.8pp vs 75% target
Max AQI Recorded
100
Moderate
Health Grade
Good
90th-pct AQI 55
Loudon County, Good days share 81.8%
National avg
Share of monitored days at AQI 0-50 (Good band).
Loudon 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 181 monitored days across EPA AQI categories.
Good
148
82%
Moderate
33
18%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Loudon County.
- PM2.5 · 110 days · 60.8%
- Ozone · 71 days · 39.2%
Health Impact Assessment
Good
Loudon County's air quality is rated Good based on 81.8% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.8% of monitored days in 2025, with a median AQI of 41. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 110 of 181 monitored days.
5-Year Air Quality Trend
Air quality is stable in Loudon County. Best year: 2022 (303 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 299 | 67 | 0 | 0 | 38 | 97 |
| 2021 | 259 | 106 | 0 | 0 | 42 | 90 |
| 2022 | 303 | 62 | 0 | 0 | 39 | 77 |
| 2023 | 264 | 96 | 1 | 0 | 42 | 107 |
| 2024 | 286 | 80 | 0 | 0 | 42 | 100 |
| 2025 | 148 | 33 | 0 | 0 | 41 | 100 |
How does Loudon County compare?
How Loudon County compares
Good-day share better than US avg
Loudon County 81.8%
Anderson County, Tennessee 91.0%
US average 76.5%
Median AQI worse than US avg
Loudon County 41
Anderson County, Tennessee 42
US average 38
Unhealthy days / yr about average
Loudon County 0
Anderson 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 Loudon County.
Albemarle County, Virginia
AQI 41 · 77.9% good
Anderson County, South Carolina
AQI 41 · 90.0% good
Berkshire County, Massachusetts
AQI 41 · 71.6% good
Berrien County, Michigan
AQI 41 · 80.9% good
Blair County, Pennsylvania
AQI 41 · 71.9% good
Bonner County, Idaho
AQI 41 · 71.3% good
What Loudon County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 41 means for exposure. Health guidance
- See how Loudon County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Loudon County with its Tennessee neighbours before drawing a conclusion about the region. All of Tennessee
Based on 181 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 Loudon County, Tennessee? ▼
Loudon County has a median Air Quality Index (AQI) of 41, rated "Good." 81.8% of monitored days (148 out of 181) had good air quality in 2025.
What is the main pollutant in Loudon County? ▼
The primary pollutant in Loudon County is Fine Particles (PM2.5), which was the main AQI driver on 110 days (61% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Loudon County have? ▼
In 2025, Loudon County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 100.
Is the air quality in Loudon County getting better or worse? ▼
Air quality in Loudon County is stable based on 5-year trends (2020-2025). Best year: 2022 with 303 good days. Worst year: 2025 with 148 good days.
What does AQI 41 mean for health? ▼
Loudon County's median AQI of 41 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 Loudon County compare to other counties in Tennessee? ▼
Loudon County has 81.8% good air days. Nearby counties in Tennessee: Anderson (91.0% good), Blount (69.6% good), Claiborne (96.3% good), Davidson (51.8% good), DeKalb (95.4% good), Dyer (79.4% good).
What is the 90th percentile AQI in Loudon County? ▼
The 90th percentile AQI for Loudon County is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 100 (Moderate).
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.