Median AQI
31
Good
Tennessee · County air quality · 2025
Montgomery County, Tennessee
Median AQI 31 (Good). 84.7% of monitored days rated Good, direct from EPA Air Quality System stations.
- 31
- Median AQI
- 84.7%
- Good-air days
- 0
- Unhealthy days
- 65%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Montgomery County's air is good on balance, cleaner than the median US county, a median AQI of 31 with 84.7% of 176 monitored days in the Good band, driven mainly by PM2.5.
- 31
- median AQI · Good
- 84.7%
- days rated Good
- PM2.5
- main pollutant
- 65%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 69.
Data updated July 2026
- Good · 149 d · 84.7%
- Moderate · 27 d · 15.3%
How did Montgomery County's air break down in 2025?
Across 176 monitored days, 149 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 69 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 176 days monitored. Median AQI: 31 (Good).
Insights: Montgomery County, Tennessee. EPA monitors recorded a median Air Quality Index of 31 across 176 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 149 (85%) fell in the Good band (AQI 0–50), 27 (15%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 54, while the worst single-day peak hit 69 (Moderate). Residents averaged about 25.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (176 days). Across the 2020–2025 trend window, good days shifted by -139 and the median AQI moved -4 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 69, 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
84.7%
149 of 176 monitored days
9.7pp vs 75% target
Max AQI Recorded
69
Moderate
Health Grade
Good
90th-pct AQI 54
Montgomery County, Good days share 84.7%
National avg
Share of monitored days at AQI 0-50 (Good band).
Montgomery 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 176 monitored days across EPA AQI categories.
Good
149
85%
Moderate
27
15%
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 Montgomery County.
- PM2.5 · 176 days · 100.0%
Health Impact Assessment
Good
Montgomery County's air quality is rated Good based on 84.7% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 84.7% of monitored days in 2025, with a median AQI of 31. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 176 of 176 monitored days.
5-Year Air Quality Trend
Air quality is improving in Montgomery County. Best year: 2024 (302 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 288 | 69 | 2 | 0 | 35 | 116 |
| 2021 | 279 | 79 | 1 | 0 | 33 | 138 |
| 2022 | 280 | 79 | 0 | 0 | 36 | 87 |
| 2023 | 271 | 79 | 1 | 0 | 36 | 105 |
| 2024 | 302 | 59 | 0 | 0 | 32 | 79 |
| 2025 | 149 | 27 | 0 | 0 | 31 | 69 |
How does Montgomery County compare?
How Montgomery County compares
Good-day share better than US avg
Montgomery County 84.7%
Anderson County, Tennessee 91.0%
US average 76.5%
Median AQI better than US avg
Montgomery County 31
Anderson County, Tennessee 42
US average 38
Unhealthy days / yr about average
Montgomery 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 Montgomery County.
Bannock County, Idaho
AQI 31 · 91.5% good
Clark County, Washington
AQI 31 · 89.3% good
Erie County, Pennsylvania
AQI 31 · 81.4% good
Honolulu County, Hawaii
AQI 31 · 95.0% good
Josephine County, Oregon
AQI 31 · 76.2% good
Monroe County, Wisconsin
AQI 31 · 75.2% good
What Montgomery 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 31 means for exposure. Health guidance
- See how Montgomery County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Montgomery County with its Tennessee neighbours before drawing a conclusion about the region. All of Tennessee
Based on 176 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 Montgomery County, Tennessee? ▼
Montgomery County has a median Air Quality Index (AQI) of 31, rated "Good." 84.7% of monitored days (149 out of 176) had good air quality in 2025.
What is the main pollutant in Montgomery County? ▼
The primary pollutant in Montgomery County is Fine Particles (PM2.5), which was the main AQI driver on 176 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Montgomery County have? ▼
In 2025, Montgomery County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 69.
Is the air quality in Montgomery County getting better or worse? ▼
Air quality in Montgomery County is improving based on 5-year trends (2020-2025). Best year: 2024 with 302 good days. Worst year: 2025 with 149 good days.
What does AQI 31 mean for health? ▼
Montgomery County's median AQI of 31 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 Montgomery County compare to other counties in Tennessee? ▼
Montgomery County has 84.7% 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 Montgomery County? ▼
The 90th percentile AQI for Montgomery County is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 69 (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.