Median AQI
38
Good
Kentucky · County air quality · 2025
Perry County, Kentucky
Median AQI 38 (Good). 84.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 38
- Median AQI
- 84.5%
- Good-air days
- 1
- Unhealthy days
- 64%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Perry County's air is good on balance, cleaner than the median US county, a median AQI of 38 with 84.5% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 38
- median AQI · Good
- 84.5%
- days rated Good
- PM2.5
- main pollutant
- 64%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 172.
Data updated July 2026
- Good · 153 d · 84.5%
- Moderate · 27 d · 14.9%
- Unhealthy · 1 d · 0.6%
How did Perry County's air break down in 2025?
Across 181 monitored days, 153 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 172 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 38 (Good).
Insights: Perry County, Kentucky. EPA monitors recorded a median Air Quality Index of 38 across 181 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 153 (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 172 (Unhealthy). Residents averaged about 25.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (97 days), Ozone (84 days). Across the 2020–2025 trend window, good days shifted by -125 and the median AQI moved -1 points, placing the multi-year trajectory at improving. Residents and visitors experienced 1 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Bell (63.5% good, AQI 43); Boone (95.1% good, AQI 38); Boyd (82.8% good, AQI 39); Bullitt (92.7% good, AQI 39); Campbell (78.5% good, AQI 39); Carter (89.8% good, AQI 36).
Air Quality Summary
Good Days
84.5%
153 of 181 monitored days
9.5pp vs 75% target
Max AQI Recorded
172
Unhealthy
Health Grade
Good
90th-pct AQI 54
Perry County, Good days share 84.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Perry County, Unhealthy-or-worse share 0.6%
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
153
85%
Moderate
27
15%
USG
0
0%
Unhealthy
1
1%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Perry County.
- PM2.5 · 97 days · 53.6%
- Ozone · 84 days · 46.4%
Health Impact Assessment
Good
Perry County's air quality is rated Good based on 84.5% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 0 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 172. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 97 of 181 monitored days.
5-Year Air Quality Trend
Air quality is improving in Perry County. Best year: 2024 (290 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 278 | 86 | 0 | 0 | 39 | 99 |
| 2021 | 247 | 118 | 0 | 0 | 44 | 93 |
| 2022 | 226 | 119 | 1 | 2 | 46 | 171 |
| 2023 | 223 | 138 | 4 | 0 | 45 | 137 |
| 2024 | 290 | 61 | 1 | 0 | 40 | 117 |
| 2025 | 153 | 27 | 0 | 1 | 38 | 172 |
How does Perry County compare?
How Perry County compares
Good-day share better than US avg
Perry County 84.5%
Bell County, Kentucky 63.5%
US average 76.5%
Median AQI about average
Perry County 38
Bell County, Kentucky 43
US average 38
Unhealthy days / yr worse than US avg
Perry County 1
Bell County, Kentucky 0
US average 0
Other Counties in Kentucky
Air quality comparison for nearby counties in Kentucky.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Perry County.
Adams County, Illinois
AQI 38 · 94.4% good
Anoka County, Minnesota
AQI 38 · 82.1% good
Atlantic County, New Jersey
AQI 38 · 79.6% good
Avery County, North Carolina
AQI 38 · 93.9% good
Barnstable County, Massachusetts
AQI 38 · 92.5% good
Bay County, Michigan
AQI 38 · 71.8% good
What Perry County's air means for you
On most days the air here is fine, but PM2.5 drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 38 means for exposure. Health guidance
- See how Perry County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Perry County with its Kentucky neighbours before drawing a conclusion about the region. All of Kentucky
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 Perry County, Kentucky? ▼
Perry County has a median Air Quality Index (AQI) of 38, rated "Good." 84.5% of monitored days (153 out of 181) had good air quality in 2025.
What is the main pollutant in Perry County? ▼
The primary pollutant in Perry County is Fine Particles (PM2.5), which was the main AQI driver on 97 days (54% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Perry County have? ▼
In 2025, Perry County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 172.
Is the air quality in Perry County getting better or worse? ▼
Air quality in Perry County is improving based on 5-year trends (2020-2025). Best year: 2024 with 290 good days. Worst year: 2025 with 153 good days.
What does AQI 38 mean for health? ▼
Perry County's median AQI of 38 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 Perry County compare to other counties in Kentucky? ▼
Perry County has 84.5% good air days. Nearby counties in Kentucky: Bell (63.5% good), Boone (95.1% good), Boyd (82.8% good), Bullitt (92.7% good), Campbell (78.5% good), Carter (89.8% good).
What is the 90th percentile AQI in Perry County? ▼
The 90th percentile AQI for Perry County is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 172 (Unhealthy).
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.