Data / Rankings / Median Air Quality Index (US EPA) / Counties in Virginia

Counties in Virginia by median Air Quality Index (US EPA), 1999

Wythe County had the highest median Air Quality Index (US EPA) of 42 counties in 1999, at 71. Northumberland County had the lowest, at 12. The median was 44. Source: the U.S. Environmental Protection Agency.

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Highest71Wythe County
Lowest12Northumberland County
Median4442 counties

Map of counties, 1999

Arlington County: 48 indexCaroline County: 35 indexCarroll County: 17 indexCharles City County: 43 indexChesterfield County: 50 indexCulpeper County: 16 indexFairfax County: 56 indexFauquier County: 51 indexFrederick County: 50 indexGiles County: 49 indexHanover County: 50 indexHenrico County: 54 indexKing William County: 14 indexLoudoun County: 44 indexMadison County: 51 indexNorthumberland County: 12 indexPage County: 52 indexPrince Edward County: 42 indexPrince William County: 37 indexRoanoke County: 34 indexRockbridge County: 61 indexRockingham County: 21 indexStafford County: 54 indexTazewell County: 13 indexWarren County: 18 indexWise County: 19 indexWythe County: 71 indexAlexandria city: 43 indexBristol city: 62 indexCharlottesville city: 17 indexChesapeake city: 56 indexFredericksburg city: 16 indexHampton city: 44 indexLynchburg city: 59 indexNewport News city: 16 indexNorfolk city: 34 indexRichmond city: 56 indexRoanoke city: 15 indexSalem city: 58 indexSuffolk city: 51 indexVirginia Beach city: 57 indexWinchester city: 19 index
  • Under 17
  • 17 to 34
  • 34 to 44
  • 44 to 51
  • 51 to 56
  • 56 and over
  • No data
index, 1999. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1999

Wythe County: 71 indexWythe County71Bristol city: 62 indexBristol city62Rockbridge County: 61 indexRockbridge County61Lynchburg city: 59 indexLynchburg city59Salem city: 58 indexSalem city58Virginia Beach city: 57 indexVirginia Beach city57Chesapeake city: 56 indexChesapeake city56Fairfax County: 56 indexFairfax County56Richmond city: 56 indexRichmond city56Henrico County: 54 indexHenrico County54Stafford County: 54 indexStafford County54Page County: 52 indexPage County52Fauquier County: 51 indexFauquier County51Madison County: 51 indexMadison County51Suffolk city: 51 indexSuffolk city51Chesterfield County: 50 indexChesterfield County50Frederick County: 50 indexFrederick County50Hanover County: 50 indexHanover County50Giles County: 49 indexGiles County49Arlington County: 48 indexArlington County48Hampton city: 44 indexHampton city44Loudoun County: 44 indexLoudoun County44Alexandria city: 43 indexAlexandria city43Charles City County: 43 indexCharles City County43Prince Edward County: 42 indexPrince Edward County42Prince William County: 37 indexPrince William County37Caroline County: 35 indexCaroline County35Norfolk city: 34 indexNorfolk city34Roanoke County: 34 indexRoanoke County34Rockingham County: 21 indexRockingham County21Winchester city: 19 indexWinchester city19Wise County: 19 indexWise County19Warren County: 18 indexWarren County18Carroll County: 17 indexCarroll County17Charlottesville city: 17 indexCharlottesville city17Culpeper County: 16 indexCulpeper County16Fredericksburg city: 16 indexFredericksburg city16Newport News city: 16 indexNewport News city16Roanoke city: 15 indexRoanoke city15King William County: 14 indexKing William County14Tazewell County: 13 indexTazewell County13Northumberland County: 12 indexNorthumberland County12Wythe County: 71 indexWythe County71Bristol city: 62 indexBristol city62Rockbridge County: 61 indexRockbridge County61Lynchburg city: 59 indexLynchburg city59Salem city: 58 indexSalem city58Virginia Beach city: 57 indexVirginia Beach city57Chesapeake city: 56 indexChesapeake city56Fairfax County: 56 indexFairfax County56Richmond city: 56 indexRichmond city56Henrico County: 54 indexHenrico County54Stafford County: 54 indexStafford County54Page County: 52 indexPage County52Fauquier County: 51 indexFauquier County51Madison County: 51 indexMadison County51Suffolk city: 51 indexSuffolk city51Chesterfield County: 50 indexChesterfield County50Frederick County: 50 indexFrederick County50Hanover County: 50 indexHanover County50Giles County: 49 indexGiles County49Arlington County: 48 indexArlington County48Hampton city: 44 indexHampton city44Loudoun County: 44 indexLoudoun County44Alexandria city: 43 indexAlexandria city43Charles City County: 43 indexCharles City County43Prince Edward County: 42 indexPrince Edward County42Prince William County: 37 indexPrince William County37Caroline County: 35 indexCaroline County35Norfolk city: 34 indexNorfolk city34Roanoke County: 34 indexRoanoke County34Rockingham County: 21 indexRockingham County21Winchester city: 19 indexWinchester city19Wise County: 19 indexWise County19Warren County: 18 indexWarren County18Carroll County: 17 indexCarroll County17Charlottesville city: 17 indexCharlottesville city17Culpeper County: 16 indexCulpeper County16Fredericksburg city: 16 indexFredericksburg city16Newport News city: 16 indexNewport News city16Roanoke city: 15 indexRoanoke city15King William County: 14 indexKing William County14Tazewell County: 13 indexTazewell County13Northumberland County: 12 indexNorthumberland County12
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties1999
index		Change on 1998
1Wythe County71+13
2Bristol city62+43
3Rockbridge County61+2
4Lynchburg city59+40
5Salem city58n/a
6Virginia Beach city57n/a
7Chesapeake city56+37
7Fairfax County56+10
7Richmond city56+19
10Henrico County54+4
10Stafford County54+3
12Page County52n/a
13Fauquier County51-3
13Madison County51+1
13Suffolk city510
16Chesterfield County500
16Frederick County50-1
16Hanover County50-14
19Giles County49+3
20Arlington County48+3
21Hampton city44-4
21Loudoun County44-2
23Alexandria city43-3
23Charles City County43+1
25Prince Edward County42+2
26Prince William County37+2
27Caroline County35-6
28Norfolk city34-2
28Roanoke County34-8
30Rockingham County21-5
31Winchester city190
31Wise County190
33Warren County18+1
34Carroll County170
34Charlottesville city17-2
36Culpeper County16+1
36Fredericksburg city160
36Newport News city16+9
39Roanoke city15+1
40King William County14-1
41Tazewell County13-3
42Northumberland County12-2

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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 1999 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: median daily AQI. 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: median daily AQI (Counties in Virginia by median Air Quality Index (US EPA), 1999) [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: median daily AQI, Counties in Virginia by median Air Quality Index (US EPA), 1999. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/virginia-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Virginia by median Air Quality Index (US EPA), 1999. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/virginia-counties.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Virginia by median Air Quality Index (US EPA), 1999 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/virginia-counties (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_virginia_by_1999,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Virginia by median Air Quality Index (US EPA), 1999}},
  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/median-air-quality-index/virginia-counties. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. 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: median daily AQI: Counties in Virginia by median Air Quality Index (US EPA), 1999
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/median-air-quality-index/virginia-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/virginia-counties.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Virginia by median Air Quality Index (US EPA) using official data, and cite the source.
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Questions

Which county has the highest median Air Quality Index (US EPA)?

Wythe County, with 71 in 1999, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Northumberland County, with 12 in 1999.

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: median daily AQI. Retrieved 2026-10-12. 18 counties have no value for 1999 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Virginia: more rankings