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

Counties in Virginia by highest daily Air Quality Index (US EPA)

Arlington County had the highest highest daily Air Quality Index (US EPA) of 43 counties in 1997, at 221. Loudoun County had the lowest, at 33. The median was 107. Source: the U.S. Environmental Protection Agency.

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Highest221Arlington County
Lowest33Loudoun County
Median10743 counties

Map of counties, 1997

Arlington County: 221 indexCaroline County: 195 indexCarroll County: 50 indexCharles City County: 202 indexChesterfield County: 172 indexCulpeper County: 66 indexFairfax County: 213 indexFauquier County: 174 indexFrederick County: 172 indexGiles County: 156 indexHanover County: 219 indexHenrico County: 195 indexHenry County: 140 indexKing William County: 59 indexLoudoun County: 33 indexMadison County: 174 indexNorthumberland County: 52 indexPrince Edward County: 159 indexPrince William County: 187 indexRoanoke County: 156 indexRockbridge County: 125 indexRockingham County: 54 indexSmyth County: 56 indexStafford County: 179 indexTazewell County: 44 indexWarren County: 62 indexWise County: 45 indexWythe County: 159 indexAlexandria city: 204 indexBristol city: 56 indexCharlottesville city: 47 indexChesapeake city: 57 indexCovington city: 53 indexFredericksburg city: 62 indexHampton city: 195 indexLynchburg city: 51 indexMartinsville city: 62 indexNewport News city: 61 indexNorfolk city: 78 indexRichmond city: 107 indexRoanoke city: 80 indexSuffolk city: 187 indexWinchester city: 67 index
  • Under 53
  • 53 to 62
  • 62 to 110
  • 110 to 170
  • 170 to 200
  • 200 and over
  • No data
index, 1997. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1997

Arlington County: 221 indexArlington County221Hanover County: 219 indexHanover County219Fairfax County: 213 indexFairfax County213Alexandria city: 204 indexAlexandria city204Charles City County: 202 indexCharles City County202Caroline County: 195 indexCaroline County195Hampton city: 195 indexHampton city195Henrico County: 195 indexHenrico County195Prince William County: 187 indexPrince William County187Suffolk city: 187 indexSuffolk city187Stafford County: 179 indexStafford County179Fauquier County: 174 indexFauquier County174Madison County: 174 indexMadison County174Chesterfield County: 172 indexChesterfield County172Frederick County: 172 indexFrederick County172Prince Edward County: 159 indexPrince Edward County159Wythe County: 159 indexWythe County159Giles County: 156 indexGiles County156Roanoke County: 156 indexRoanoke County156Henry County: 140 indexHenry County140Rockbridge County: 125 indexRockbridge County125Richmond city: 107 indexRichmond city107Roanoke city: 80 indexRoanoke city80Norfolk city: 78 indexNorfolk city78Winchester city: 67 indexWinchester city67Culpeper County: 66 indexCulpeper County66Fredericksburg city: 62 indexFredericksburg city62Martinsville city: 62 indexMartinsville city62Warren County: 62 indexWarren County62Newport News city: 61 indexNewport News city61King William County: 59 indexKing William County59Chesapeake city: 57 indexChesapeake city57Bristol city: 56 indexBristol city56Smyth County: 56 indexSmyth County56Rockingham County: 54 indexRockingham County54Covington city: 53 indexCovington city53Northumberland County: 52 indexNorthumberland County52Lynchburg city: 51 indexLynchburg city51Carroll County: 50 indexCarroll County50Charlottesville city: 47 indexCharlottesville city47Wise County: 45 indexWise County45Tazewell County: 44 indexTazewell County44Loudoun County: 33 indexLoudoun County33Arlington County: 221 indexArlington County221Hanover County: 219 indexHanover County219Fairfax County: 213 indexFairfax County213Alexandria city: 204 indexAlexandria city204Charles City County: 202 indexCharles City County202Caroline County: 195 indexCaroline County195Hampton city: 195 indexHampton city195Henrico County: 195 indexHenrico County195Prince William County: 187 indexPrince William County187Suffolk city: 187 indexSuffolk city187Stafford County: 179 indexStafford County179Fauquier County: 174 indexFauquier County174Madison County: 174 indexMadison County174Chesterfield County: 172 indexChesterfield County172Frederick County: 172 indexFrederick County172Prince Edward County: 159 indexPrince Edward County159Wythe County: 159 indexWythe County159Giles County: 156 indexGiles County156Roanoke County: 156 indexRoanoke County156Henry County: 140 indexHenry County140Rockbridge County: 125 indexRockbridge County125Richmond city: 107 indexRichmond city107Roanoke city: 80 indexRoanoke city80Norfolk city: 78 indexNorfolk city78Winchester city: 67 indexWinchester city67Culpeper County: 66 indexCulpeper County66Fredericksburg city: 62 indexFredericksburg city62Martinsville city: 62 indexMartinsville city62Warren County: 62 indexWarren County62Newport News city: 61 indexNewport News city61King William County: 59 indexKing William County59Chesapeake city: 57 indexChesapeake city57Bristol city: 56 indexBristol city56Smyth County: 56 indexSmyth County56Rockingham County: 54 indexRockingham County54Covington city: 53 indexCovington city53Northumberland County: 52 indexNorthumberland County52Lynchburg city: 51 indexLynchburg city51Carroll County: 50 indexCarroll County50Charlottesville city: 47 indexCharlottesville city47Wise County: 45 indexWise County45Tazewell County: 44 indexTazewell County44Loudoun County: 33 indexLoudoun County33
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties1997
index		Change on 1996
1Arlington County221+70
2Hanover County219+76
3Fairfax County213+13
4Alexandria city204+40
5Charles City County202+38
6Caroline County195+29
6Hampton city195+39
6Henrico County195+41
9Prince William County187+28
9Suffolk city187+36
11Stafford County179+5
12Fauquier County174+13
12Madison County174+20
14Chesterfield County172+16
14Frederick County172+22
16Prince Edward County159+26
16Wythe County159+33
18Giles County156+6
18Roanoke County156+37
20Henry County140-19
21Rockbridge County125+10
22Richmond city107+9
23Roanoke city80+2
24Norfolk city78+2
25Winchester city67+25
26Culpeper County66+26
27Fredericksburg city62+8
27Martinsville city62+15
27Warren County62+26
30Newport News city61+16
31King William County59+2
32Chesapeake city57+13
33Bristol city56+1
33Smyth County56-7
35Rockingham County54n/a
36Covington city53-1
37Northumberland County52+6
38Lynchburg city51+8
39Carroll County50-5
40Charlottesville city47+11
41Wise County45-11
42Tazewell County44-12
43Loudoun County33-21

Other periods

About this ranking

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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. 17 counties with data in other periods have no value for 1997 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: highest 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: highest daily AQI (Counties in Virginia by highest daily Air Quality Index (US EPA), 1997) [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: highest daily AQI, Counties in Virginia by highest daily Air Quality Index (US EPA), 1997. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/virginia-counties?period=1997. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Virginia by highest daily Air Quality Index (US EPA), 1997. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/virginia-counties?period=1997.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Virginia by highest daily Air Quality Index (US EPA), 1997 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/virginia-counties?period=1997 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_virginia_by_1997,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Virginia by highest daily Air Quality Index (US EPA), 1997}},
  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/highest-daily-air-quality-index/virginia-counties?period=1997. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Counties in Virginia by highest daily Air Quality Index (US EPA), 1997
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/highest-daily-air-quality-index/virginia-counties?period=1997
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/virginia-counties?period=1997.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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 highest daily Air Quality Index (US EPA) using official data, and cite the source.
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Questions

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

Arlington County, with 221 in 1997, according to the U.S. Environmental Protection Agency.

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

Loudoun County, with 33 in 1997.

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: highest daily AQI. Retrieved 2026-10-12. 17 counties have no value for 1997 and are not ranked.

Highest daily Air Quality Index (US EPA): other rankings

Counties in Virginia: more rankings