State air quality · 2025

West Virginia Air Quality Ranking

Across 13 monitored counties, the typical county in West Virginia posts a median AQI of 39 (Good) and 78.2% of monitored days were rated Good, from EPA AQS.

39
Avg median AQI
78.2%
Good-air days
13
Counties monitored
58%
Cleaner than US states

West Virginia's typical county median AQI is 39 (Good) across 13 monitored counties

According to the U.S. EPA Air Quality System, West Virginia monitors 13 counties with a day-weighted Good-day share of 78.2%. Cleanest: Tucker County (94.2% Good). Most polluted: Marshall County (63.7%). These are annual summaries, not live AirNow readings.

Data source EPA Air Quality System (AQS)

Cleaner than US states
West Virginia's day-weighted Good-day share of 78.2% places it cleaner than 58% of US states.
In-state spread
Within West Virginia, Tucker County leads at 94.2% Good days while Marshall County sits at 63.7% across 13 monitored counties.
2024→2025 release
West Virginia's Good-day share moved -1.0 points vs the 2024 EPA annual release.
Typical median AQI
Typical median AQI: 39

Verify with AirNow → · EPA AQS →

EPA state monitoring brief

AQS state key WEST-VIRGINIA

West Virginia · 2025 EPA AQS · 13 counties · med AQI 39 · 78.2% Good · Tucker→Marshall spread

  • GOOD 39 Median AQI · Good
  • SHARE 78.2% Good-day share
  • COUNT 13 Counties monitored
  • UNH 0 Unhealthy+ days
  • RANK 58% Cleaner than states
  • PM25 50.4% Main pollutant share

Good-day share peers

North Dakota79.4%Idaho78.2%West Virginia (this)78.2%Florida77.4%
Good-day share neighbourhood · nearest ABS peers vs West Virginia

West Virginia's 78.2% Good-day share is cleaner than 58% of monitored US states; Tucker and Marshall County bracket the in-state range. Open Tucker County →

According to EPA AQS annual summaries on PlainAirData, West Virginia ranks #22 of 52 by day-weighted good-day share (78.2%) and #24 by mean county median AQI (38.8). Hawaii is #1 of 52 by day-weighted good-day share (93.8% of monitored days) at mean county median-AQI #4 (27.3) ≠ Alaska #1 lowest mean county median AQI (20.3) at good-day share #8 (84.4%).

Data updated August 2026

What changed, what drives it, and how thick is the sample

Three derived views WPR-style word count does not substitute for: release-over-release movement from county annual rows, the EPA main-pollutant day mix, and how many counties sit below the 100-day ranking floor.

Release change

78.2%

Good-day share in 2025, down 1.0 percentage points vs 2024. County-mean median AQI 39, 0.6 points lower (cleaner) than 2024.

Pollutant mix

PM2.5

Main driver on 50.4% of pollutant-assigned days.

  • PM2.5 50.4%
  • Ozone 49.6%

Monitoring coverage

279

Average monitored days per county in the latest release. Every monitored county clears the 100-day ranking floor.

Counties Monitored

13

Good Days %

78.2%

Avg Median AQI

39

Total Unhealthy Days

0

Best Air Quality

Tucker County

Worst Air Quality

Marshall County

Where West Virginia sits nationally

COUNT-derived placement among 52 US states with at least 365 monitored days in the latest county release. West Virginia's day-weighted Good-day share is 78.2% - cleaner than 58% of that comparison set.

West Virginia Good-day share vs. every US state

Day-weighted share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release

78.2% Cleaner than 58% higher than 58% of 52 US states

0.0%–5.0%: 0 US states (0%). Below this entry. 5.0%–10.0%: 0 US states (0%). Below this entry. 10.0%–15.0%: 0 US states (0%). Below this entry. 15.0%–20.0%: 0 US states (0%). Below this entry. 20.0%–25.0%: 0 US states (0%). Below this entry. 25.0%–30.0%: 0 US states (0%). Below this entry. 30.0%–35.0%: 0 US states (0%). Below this entry. 35.0%–40.0%: 0 US states (0%). Below this entry. 40.0%–45.0%: 0 US states (0%). Below this entry. 45.0%–50.0%: 0 US states (0%). Below this entry. 50.0%–55.0%: 0 US states (0%). Below this entry. 55.0%–60.0%: 0 US states (0%). Below this entry. 60.0%–65.0%: 2 US states (4%). Below this entry. 65.0%–70.0%: 9 US states (17%). Below this entry. 70.0%–75.0%: 11 US states (21%). Below this entry. 75.0%–80.0%: 11 US states (21%). This entry sits in this band. 80.0%–85.0%: 13 US states (25%). Above this entry. 85.0%–90.0%: 5 US states (10%). Above this entry. 90.0%–95.0%: 1 US states (2%). Above this entry. 95.0%–100.0%: 0 US states (0%). Above this entry. 100.0%–105.0%: 0 US states (0%). Above this entry. This state 0.0% 100% every floor-qualified US state, bucketed by value

Each bar is a band; taller bars hold more US states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025

Which counties in West Virginia have the cleanest and most polluted air?

Cleanest counties in West Virginia

Share of monitored days rated Good (AQI 0–50)

  1. 1 Tucker County 94.2%
  2. 2 Greenbrier County 93%
  3. 3 Berkeley County 83.6%
  4. 4 Wood County 82.9%
  5. 5 Ohio County 80.9%
  6. 6 Monongalia County 79.8%
  7. 7 Kanawha County 77%
  8. 8 Marion County 74.2%
  9. 9 Brooke County 73.1%
  10. 10 Harrison County 72.4%
  11. 11 Hancock County 69.9%
  12. 12 Cabell County 69.5%

Good-day share · EPA Air Quality System

County Good % Median AQI
Tucker 94.2% 36
Greenbrier 93.0% 37
Berkeley 83.6% 39
Wood 82.9% 39
Ohio 80.9% 40
Monongalia 79.8% 42
Kanawha 77.0% 39
Marion 74.2% 37
Brooke 73.0% 36
Harrison 72.4% 33
Hancock 69.9% 42
Cabell 69.5% 42
Marshall 63.7% 42

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025. See our methodology for how AQI and median figures are computed.

Coverage: 13 counties in West Virginia with active monitoring stations. Unmonitored counties are not represented.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files, aggregated to the state level · 2020–2025

Every figure on PlainAirData 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.

Informational only, not professional advice. Data from EPA AQS. See our disclaimer.