Median AQI
32
Good
West Virginia · County air quality · 2025
Harrison County, West Virginia
Median AQI 32 (Good). 73.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 32
- Median AQI
- 73.3%
- Good-air days
- 0
- Unhealthy days
- 38%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Harrison County's air is good on balance, more polluted than the median US county, a median AQI of 32 with 73.3% of 60 monitored days in the Good band, driven mainly by PM2.5.
- 32
- median AQI · Good
- 73.3%
- days rated Good
- PM2.5
- main pollutant
- 38%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 68.
Data updated July 2026
- Good · 44 d · 73.3%
- Moderate · 16 d · 26.7%
How did Harrison County's air break down in 2025?
Across 60 monitored days, 44 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 68 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 60 days monitored. Median AQI: 32 (Good).
Insights: Harrison County, West Virginia. EPA monitors recorded a median Air Quality Index of 32 across 60 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 44 (73%) fell in the Good band (AQI 0–50), 16 (27%) 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 68 (Moderate). Residents averaged about 22.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (60 days). Across the 2020–2025 trend window, good days shifted by -55 and the median AQI moved -3 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 68, moderate but never Unhealthy. Nearby counties show comparable readings: Berkeley (81.1% good, AQI 40); Brooke (79.3% good, AQI 35); Cabell (74.0% good, AQI 41); Greenbrier (89.3% good, AQI 42); Hancock (74.6% good, AQI 42); Kanawha (79.6% good, AQI 40).
Air Quality Summary
Good Days
73.3%
44 of 60 monitored days
-1.7pp vs 75% target
Max AQI Recorded
68
Moderate
Health Grade
Moderate
90th-pct AQI 55
Harrison County, Good days share 73.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Harrison 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 60 monitored days across EPA AQI categories.
Good
44
73%
Moderate
16
27%
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 Harrison County.
- PM2.5 · 60 days · 100.0%
Health Impact Assessment
Moderate
Harrison County's air quality is rated Moderate based on 73.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 73.3% of monitored days in 2025, with a median AQI of 32. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 60 of 60 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Harrison County. Best year: 2020 (99 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 99 | 19 | 0 | 0 | 35 | 80 |
| 2021 | 82 | 33 | 0 | 0 | 35 | 69 |
| 2022 | 93 | 20 | 0 | 0 | 34 | 69 |
| 2023 | 82 | 24 | 0 | 1 | 39 | 166 |
| 2024 | 91 | 22 | 0 | 0 | 34 | 60 |
| 2025 | 44 | 16 | 0 | 0 | 32 | 68 |
How does Harrison County compare?
How Harrison County compares
Good-day share worse than US avg
Harrison County 73.3%
Berkeley County, West Virginia 81.1%
US average 76.5%
Median AQI better than US avg
Harrison County 32
Berkeley County, West Virginia 40
US average 38
Unhealthy days / yr about average
Harrison County 0
Berkeley County, West Virginia 0
US average 0
Other Counties in West Virginia
Air quality comparison for nearby counties in West Virginia.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Harrison County.
Archuleta County, Colorado
AQI 32 · 79.5% good
Clay County, Alabama
AQI 32 · 85.4% good
Elmore County, Alabama
AQI 32 · 97.2% good
Klamath County, Oregon
AQI 32 · 71.3% good
Liberty County, Florida
AQI 32 · 97.7% good
Schoolcraft County, Michigan
AQI 32 · 89.4% good
What Harrison 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 32 means for exposure. Health guidance
- See how Harrison County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Harrison County with its West Virginia neighbours before drawing a conclusion about the region. All of West Virginia
Based on 60 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 Harrison County, West Virginia? ▼
Harrison County has a median Air Quality Index (AQI) of 32, rated "Good." 73.3% of monitored days (44 out of 60) had good air quality in 2025.
What is the main pollutant in Harrison County? ▼
The primary pollutant in Harrison County is Fine Particles (PM2.5), which was the main AQI driver on 60 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Harrison County have? ▼
In 2025, Harrison County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 68.
Is the air quality in Harrison County getting better or worse? ▼
Air quality in Harrison County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 99 good days. Worst year: 2025 with 44 good days.
What does AQI 32 mean for health? ▼
Harrison County's median AQI of 32 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 Harrison County compare to other counties in West Virginia? ▼
Harrison County has 73.3% good air days. Nearby counties in West Virginia: Berkeley (81.1% good), Brooke (79.3% good), Cabell (74.0% good), Greenbrier (89.3% good), Hancock (74.6% good), Kanawha (79.6% good).
What is the 90th percentile AQI in Harrison County? ▼
The 90th percentile AQI for Harrison County is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 68 (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.