Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in West Virginia

Counties in West Virginia by share of days with good air quality (US EPA AQI)

Wayne County had the highest share of days with good air quality (US EPA AQI) of 18 counties in 2003, at 94.9%. Marion County had the lowest, at 17.5%. The median was 53%. Source: EPA.

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Highest94.9Wayne County
Lowest17.5Marion County
Median5318 counties

Map of counties, 2003

Berkeley County: 50.4 %Brooke County: 65.7 %Cabell County: 45.6 %Gilmer County: 90.1 %Greenbrier County: 67.1 %Hancock County: 58.9 %Harrison County: 25.4 %Kanawha County: 59.7 %Marion County: 17.5 %Marshall County: 20.7 %Mercer County: 44.6 %Monongalia County: 51.3 %Ohio County: 66.3 %Raleigh County: 39.7 %Summers County: 54.7 %Tucker County: 77.1 %Wayne County: 94.9 %Wood County: 46.7 %
  • Under 42
  • 42 to 50
  • 50 to 59
  • 59 to 67
  • 67 and over
  • No data
%, 2003. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2003

Wayne County: 94.9 %Wayne County94.9Gilmer County: 90.1 %Gilmer County90.1Tucker County: 77.1 %Tucker County77.1Greenbrier County: 67.1 %Greenbrier County67.1Ohio County: 66.3 %Ohio County66.3Brooke County: 65.7 %Brooke County65.7Kanawha County: 59.7 %Kanawha County59.7Hancock County: 58.9 %Hancock County58.9Summers County: 54.7 %Summers County54.7Monongalia County: 51.3 %Monongalia County51.3Berkeley County: 50.4 %Berkeley County50.4Wood County: 46.7 %Wood County46.7Cabell County: 45.6 %Cabell County45.6Mercer County: 44.6 %Mercer County44.6Raleigh County: 39.7 %Raleigh County39.7Harrison County: 25.4 %Harrison County25.4Marshall County: 20.7 %Marshall County20.7Marion County: 17.5 %Marion County17.5Wayne County: 94.9 %Wayne County94.9Gilmer County: 90.1 %Gilmer County90.1Tucker County: 77.1 %Tucker County77.1Greenbrier County: 67.1 %Greenbrier County67.1Ohio County: 66.3 %Ohio County66.3Brooke County: 65.7 %Brooke County65.7Kanawha County: 59.7 %Kanawha County59.7Hancock County: 58.9 %Hancock County58.9Summers County: 54.7 %Summers County54.7Monongalia County: 51.3 %Monongalia County51.3Berkeley County: 50.4 %Berkeley County50.4Wood County: 46.7 %Wood County46.7Cabell County: 45.6 %Cabell County45.6Mercer County: 44.6 %Mercer County44.6Raleigh County: 39.7 %Raleigh County39.7Harrison County: 25.4 %Harrison County25.4Marshall County: 20.7 %Marshall County20.7Marion County: 17.5 %Marion County17.5
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2003 (%)Change on 2002
1Wayne County94.9n/a
2Gilmer County90.1+6 pts
3Tucker County77.1+4.4 pts
4Greenbrier County67.1+4.4 pts
5Ohio County66.3+6.1 pts
6Brooke County65.7+1.6 pts
7Kanawha County59.7+4.9 pts
8Hancock County58.9+5.2 pts
9Summers County54.7-2.6 pts
10Monongalia County51.3+1.1 pts
11Berkeley County50.4+4.2 pts
12Wood County46.7+5.7 pts
13Cabell County45.6+4.7 pts
14Mercer County44.6+7.8 pts
15Raleigh County39.7+6.9 pts
16Harrison County25.4-8.5 pts
17Marshall County20.7-5.2 pts
18Marion County17.5-5.3 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 2 counties with data in other periods have no value for 2003 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts (Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_west_virginia_2003,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in West Virginia by share of days with good air quality (US EPA AQI), 2003
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/west-virginia-counties?period=2003.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Wayne County, with 94.9% in 2003, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Marion County, with 17.5% in 2003.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 2 counties have no value for 2003 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in West Virginia: more rankings