Median AQI
38
Good
Pennsylvania · County air quality · 2025
Elk County, Pennsylvania
Median AQI 38 (Good). 94.7% of monitored days rated Good, direct from EPA Air Quality System stations.
- 38
- Median AQI
- 94.7%
- Good-air days
- 0
- Unhealthy days
- 88%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Elk County's air is good on balance, cleaner than most US counties, a median AQI of 38 with 94.7% of 243 monitored days in the Good band, driven mainly by Ozone.
- 38
- median AQI · Good
- 94.7%
- days rated Good
- Ozone
- main pollutant
- 88%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 84.
Data updated July 2026
- Good · 230 d · 94.7%
- Moderate · 13 d · 5.3%
How did Elk County's air break down in 2025?
Across 243 monitored days, 230 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 84 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 243 days monitored. Median AQI: 38 (Good).
Insights: Elk County, Pennsylvania. EPA monitors recorded a median Air Quality Index of 38 across 243 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 230 (95%) fell in the Good band (AQI 0–50), 13 (5%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 48, while the worst single-day peak hit 84 (Moderate). Residents averaged about 28.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (243 days). Across the 2020–2025 trend window, good days shifted by -126 and the median AQI moved +4 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 84, 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
94.7%
230 of 243 monitored days
19.7pp vs 75% target
Max AQI Recorded
84
Moderate
Health Grade
Excellent
90th-pct AQI 48
Elk County, Good days share 94.7%
National avg
Share of monitored days at AQI 0-50 (Good band).
Elk 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 243 monitored days across EPA AQI categories.
Good
230
95%
Moderate
13
5%
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 Elk County.
- Ozone · 243 days · 100.0%
Health Impact Assessment
Excellent
Elk County's air quality is rated Excellent based on 94.7% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 94.7% of monitored days in 2025, with a median AQI of 38. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 243 of 243 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Elk County. Best year: 2020 (356 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 356 | 2 | 0 | 0 | 34 | 67 |
| 2021 | 340 | 18 | 0 | 0 | 34 | 87 |
| 2022 | 353 | 9 | 1 | 0 | 35 | 101 |
| 2023 | 343 | 20 | 0 | 0 | 35 | 100 |
| 2024 | 343 | 15 | 0 | 0 | 34 | 67 |
| 2025 | 230 | 13 | 0 | 0 | 38 | 84 |
How does Elk County compare?
How Elk County compares
Good-day share better than US avg
Elk County 94.7%
Adams County, Pennsylvania 73.8%
US average 76.5%
Median AQI about average
Elk County 38
Adams County, Pennsylvania 42
US average 38
Unhealthy days / yr about average
Elk 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 Elk 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 Elk 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 38 means for exposure. Health guidance
- See how Elk County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Elk County with its Pennsylvania neighbours before drawing a conclusion about the region. All of Pennsylvania
Based on 243 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 Elk County, Pennsylvania? ▼
Elk County has a median Air Quality Index (AQI) of 38, rated "Good." 94.7% of monitored days (230 out of 243) had good air quality in 2025.
What is the main pollutant in Elk County? ▼
The primary pollutant in Elk County is Ozone (O3), which was the main AQI driver on 243 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Elk County have? ▼
In 2025, Elk County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 84.
Is the air quality in Elk County getting better or worse? ▼
Air quality in Elk County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 356 good days. Worst year: 2025 with 230 good days.
What does AQI 38 mean for health? ▼
Elk 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 Elk County compare to other counties in Pennsylvania? ▼
Elk County has 94.7% 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 Elk County? ▼
The 90th percentile AQI for Elk County is 48, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 84 (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.