Median AQI
41
Good
Pennsylvania · County air quality · 2025
Fayette County, Pennsylvania
Median AQI 41 (Good). 76.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 76.9%
- Good-air days
- 0
- Unhealthy days
- 43%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Fayette County's air is good on balance, more polluted than the median US county, a median AQI of 41 with 76.9% of 212 monitored days in the Good band, driven mainly by Ozone.
- 41
- median AQI · Good
- 76.9%
- days rated Good
- Ozone
- main pollutant
- 43%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 93.
Data updated July 2026
- Good · 163 d · 76.9%
- Moderate · 49 d · 23.1%
How did Fayette County's air break down in 2025?
Across 212 monitored days, 163 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 93 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 212 days monitored. Median AQI: 41 (Good).
Insights: Fayette County, Pennsylvania. EPA monitors recorded a median Air Quality Index of 41 across 212 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 163 (77%) fell in the Good band (AQI 0–50), 49 (23%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 58, while the worst single-day peak hit 93 (Moderate). Residents averaged about 23.1 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (141 days), PM2.5 (71 days). Across the 2020–2025 trend window, good days shifted by -102 and the median AQI moved -1 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 93, moderate but never Unhealthy. Nearby counties show comparable readings: Adams (73.8% good, AQI 42); Allegheny (51.6% good, AQI 49); Armstrong (68.1% good, AQI 42); Beaver (54.3% good, AQI 47); Berks (65.6% good, AQI 44); Blair (71.9% good, AQI 41).
Air Quality Summary
Good Days
76.9%
163 of 212 monitored days
1.9pp vs 75% target
Max AQI Recorded
93
Moderate
Health Grade
Good
90th-pct AQI 58
Fayette County, Good days share 76.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Fayette 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 212 monitored days across EPA AQI categories.
Good
163
77%
Moderate
49
23%
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 Fayette County.
- Ozone · 141 days · 66.5%
- PM2.5 · 71 days · 33.5%
Health Impact Assessment
Good
Fayette County's air quality is rated Good based on 76.9% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 76.9% 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 Ozone, driving AQI on 141 of 212 monitored days.
5-Year Air Quality Trend
Air quality is improving in Fayette County. Best year: 2024 (269 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 265 | 98 | 0 | 0 | 42 | 100 |
| 2021 | 227 | 126 | 1 | 0 | 43 | 113 |
| 2022 | 218 | 84 | 0 | 0 | 43 | 87 |
| 2023 | 220 | 82 | 2 | 0 | 44 | 129 |
| 2024 | 269 | 95 | 2 | 0 | 42 | 101 |
| 2025 | 163 | 49 | 0 | 0 | 41 | 93 |
How does Fayette County compare?
How Fayette County compares
Good-day share about average
Fayette County 76.9%
Adams County, Pennsylvania 73.8%
US average 76.5%
Median AQI worse than US avg
Fayette County 41
Adams County, Pennsylvania 42
US average 38
Unhealthy days / yr about average
Fayette County 0
Adams County, Pennsylvania 0
US average 0
Other Counties in Pennsylvania
Air quality comparison for nearby counties in Pennsylvania.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Fayette 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 Fayette 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 41 means for exposure. Health guidance
- See how Fayette County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Fayette County with its Pennsylvania neighbours before drawing a conclusion about the region. All of Pennsylvania
Based on 212 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 Fayette County, Pennsylvania? ▼
Fayette County has a median Air Quality Index (AQI) of 41, rated "Good." 76.9% of monitored days (163 out of 212) had good air quality in 2025.
What is the main pollutant in Fayette County? ▼
The primary pollutant in Fayette County is Ozone (O3), which was the main AQI driver on 141 days (67% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Fayette County have? ▼
In 2025, Fayette County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 93.
Is the air quality in Fayette County getting better or worse? ▼
Air quality in Fayette County is improving based on 5-year trends (2020-2025). Best year: 2024 with 269 good days. Worst year: 2025 with 163 good days.
What does AQI 41 mean for health? ▼
Fayette 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 Fayette County compare to other counties in Pennsylvania? ▼
Fayette County has 76.9% good air days. Nearby counties in Pennsylvania: Adams (73.8% good), Allegheny (51.6% good), Armstrong (68.1% good), Beaver (54.3% good), Berks (65.6% good), Blair (71.9% good).
What is the 90th percentile AQI in Fayette County? ▼
The 90th percentile AQI for Fayette County is 58, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 93 (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.