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

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

Campbell County had the highest share of days with good air quality (US EPA AQI) of 42 counties in 1990, at 100%. Fairfax County had the lowest, at 40.8%. The median was 79.9%. Source: EPA.

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Highest100Campbell County
Lowest40.8Fairfax County
Median79.942 counties

Map of counties, 1990

Amherst County: 59.5 %Arlington County: 61.1 %Augusta County: 78.5 %Buchanan County: 86.8 %Campbell County: 100 %Carroll County: 95.1 %Charles City County: 58.5 %Chesterfield County: 77.4 %Fairfax County: 40.8 %Fauquier County: 64.6 %Giles County: 60.4 %Hanover County: 58.5 %Henrico County: 70.3 %King William County: 98.3 %Loudoun County: 97.4 %Madison County: 59.3 %Northampton County: 61.2 %Prince Edward County: 68.9 %Prince William County: 100 %Roanoke County: 79.7 %Smyth County: 96.7 %Warren County: 71.4 %Wythe County: 60.2 %York County: 98.3 %Alexandria city: 65.2 %Bristol city: 96.7 %Charlottesville city: 98.3 %Chesapeake city: 100 %Covington city: 89.1 %Fairfax city: 71.8 %Fredericksburg city: 98.3 %Hampton city: 74.9 %Hopewell city: 96.7 %Lynchburg city: 100 %Martinsville city: 100 %Newport News city: 100 %Norfolk city: 86.8 %Portsmouth city: 98.4 %Richmond city: 80 %Roanoke city: 77 %Suffolk city: 51.3 %Winchester city: 98.3 %
  • Under 60
  • 60 to 71
  • 71 to 80
  • 80 to 97
  • 97 to 98
  • 98 and over
  • No data
%, 1990. 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, 1990

Campbell County: 100 %Campbell County100Chesapeake city: 100 %Chesapeake city100Lynchburg city: 100 %Lynchburg city100Martinsville city: 100 %Martinsville city100Newport News city: 100 %Newport News city100Prince William County: 100 %Prince William County100Portsmouth city: 98.4 %Portsmouth city98.4Charlottesville city: 98.3 %Charlottesville city98.3Fredericksburg city: 98.3 %Fredericksburg city98.3King William County: 98.3 %King William County98.3Winchester city: 98.3 %Winchester city98.3York County: 98.3 %York County98.3Loudoun County: 97.4 %Loudoun County97.4Bristol city: 96.7 %Bristol city96.7Hopewell city: 96.7 %Hopewell city96.7Smyth County: 96.7 %Smyth County96.7Carroll County: 95.1 %Carroll County95.1Covington city: 89.1 %Covington city89.1Buchanan County: 86.8 %Buchanan County86.8Norfolk city: 86.8 %Norfolk city86.8Richmond city: 80 %Richmond city80Roanoke County: 79.7 %Roanoke County79.7Augusta County: 78.5 %Augusta County78.5Chesterfield County: 77.4 %Chesterfield County77.4Roanoke city: 77 %Roanoke city77Hampton city: 74.9 %Hampton city74.9Fairfax city: 71.8 %Fairfax city71.8Warren County: 71.4 %Warren County71.4Henrico County: 70.3 %Henrico County70.3Prince Edward County: 68.9 %Prince Edward County68.9Alexandria city: 65.2 %Alexandria city65.2Fauquier County: 64.6 %Fauquier County64.6Northampton County: 61.2 %Northampton County61.2Arlington County: 61.1 %Arlington County61.1Giles County: 60.4 %Giles County60.4Wythe County: 60.2 %Wythe County60.2Amherst County: 59.5 %Amherst County59.5Madison County: 59.3 %Madison County59.3Charles City County: 58.5 %Charles City County58.5Hanover County: 58.5 %Hanover County58.5Suffolk city: 51.3 %Suffolk city51.3Fairfax County: 40.8 %Fairfax County40.8Campbell County: 100 %Campbell County100Chesapeake city: 100 %Chesapeake city100Lynchburg city: 100 %Lynchburg city100Martinsville city: 100 %Martinsville city100Newport News city: 100 %Newport News city100Prince William County: 100 %Prince William County100Portsmouth city: 98.4 %Portsmouth city98.4Charlottesville city: 98.3 %Charlottesville city98.3Fredericksburg city: 98.3 %Fredericksburg city98.3King William County: 98.3 %King William County98.3Winchester city: 98.3 %Winchester city98.3York County: 98.3 %York County98.3Loudoun County: 97.4 %Loudoun County97.4Bristol city: 96.7 %Bristol city96.7Hopewell city: 96.7 %Hopewell city96.7Smyth County: 96.7 %Smyth County96.7Carroll County: 95.1 %Carroll County95.1Covington city: 89.1 %Covington city89.1Buchanan County: 86.8 %Buchanan County86.8Norfolk city: 86.8 %Norfolk city86.8Richmond city: 80 %Richmond city80Roanoke County: 79.7 %Roanoke County79.7Augusta County: 78.5 %Augusta County78.5Chesterfield County: 77.4 %Chesterfield County77.4Roanoke city: 77 %Roanoke city77Hampton city: 74.9 %Hampton city74.9Fairfax city: 71.8 %Fairfax city71.8Warren County: 71.4 %Warren County71.4Henrico County: 70.3 %Henrico County70.3Prince Edward County: 68.9 %Prince Edward County68.9Alexandria city: 65.2 %Alexandria city65.2Fauquier County: 64.6 %Fauquier County64.6Northampton County: 61.2 %Northampton County61.2Arlington County: 61.1 %Arlington County61.1Giles County: 60.4 %Giles County60.4Wythe County: 60.2 %Wythe County60.2Amherst County: 59.5 %Amherst County59.5Madison County: 59.3 %Madison County59.3Charles City County: 58.5 %Charles City County58.5Hanover County: 58.5 %Hanover County58.5Suffolk city: 51.3 %Suffolk city51.3Fairfax County: 40.8 %Fairfax County40.8
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties1990 (%)Change on 1989
1Campbell County1000 pts
1Chesapeake city100+6.7 pts
1Lynchburg city100+1.7 pts
1Martinsville city100+1.8 pts
1Newport News city1000 pts
1Prince William County100n/a
7Portsmouth city98.4-1.6 pts
8Charlottesville city98.3+4.9 pts
8Fredericksburg city98.3-1.7 pts
8King William County98.3n/a
8Winchester city98.3+3.6 pts
8York County98.3-1.7 pts
13Loudoun County97.4n/a
14Bristol city96.7+4.8 pts
14Hopewell city96.7+0.1 pts
14Smyth County96.7+32.4 pts
17Carroll County95.1+1.3 pts
18Covington city89.1-0.9 pts
19Buchanan County86.8-2.1 pts
19Norfolk city86.8+1 pts
21Richmond city80+3 pts
22Roanoke County79.7+4.6 pts
23Augusta County78.5-6.4 pts
24Chesterfield County77.4+17.7 pts
25Roanoke city77-8.5 pts
26Hampton city74.9-3.8 pts
27Fairfax city71.8+1.7 pts
28Warren County71.4-1.5 pts
29Henrico County70.3-9.1 pts
30Prince Edward County68.9n/a
31Alexandria city65.2+0.3 pts
32Fauquier County64.6+5.7 pts
33Northampton County61.2+4.7 pts
34Arlington County61.1-3.3 pts
35Giles County60.4n/a
36Wythe County60.2n/a
37Amherst County59.5n/a
38Madison County59.3-11 pts
39Charles City County58.5-22.5 pts
39Hanover County58.5+5.7 pts
41Suffolk city51.3-25 pts
42Fairfax County40.8-3 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. 18 counties with data in other periods have no value for 1990 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 Virginia by share of days with good air quality (US EPA AQI), 1990) [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 Virginia by share of days with good air quality (US EPA AQI), 1990. 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/virginia-counties?period=1990. 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 Virginia by share of days with good air quality (US EPA AQI), 1990. 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/virginia-counties?period=1990.

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 Virginia by share of days with good air quality (US EPA AQI), 1990 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/virginia-counties?period=1990 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_virginia_by_1990,
  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 Virginia by share of days with good air quality (US EPA AQI), 1990}},
  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/virginia-counties?period=1990. 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 Virginia by share of days with good air quality (US EPA AQI), 1990
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/virginia-counties?period=1990
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/virginia-counties?period=1990.
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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Rank Counties in Virginia by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

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

Campbell County, with 100% in 1990, according to EPA.

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

Fairfax County, with 40.8% in 1990.

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. 18 counties have no value for 1990 and are not ranked.

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

Counties in Virginia: more rankings