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

Charles City County had the highest highest daily Air Quality Index (US EPA) of 42 counties in 1999, at 223. Tazewell County had the lowest, at 33. The median was 161. Source: the U.S. Environmental Protection Agency.

Highest223Charles City County

Lowest33Tazewell County

Median16142 counties

All counties, 1999

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Rank	Counties	1999 index	Change on 1998
1	Charles City County	223	+6
2	Fairfax County	210	-3
3	Stafford County	207	+1
4	Suffolk city	206	+24
5	Hanover County	204	-5
6	Hampton city	203	+24
7	Henrico County	202	-8
8	Loudoun County	201	-1
9	Arlington County	200	+15
10	Caroline County	195	-15
11	Alexandria city	192	+2
12	Madison County	190	-15
13	Chesterfield County	185	-17
13	Roanoke County	185	-21
15	Rockbridge County	182	+78
16	Page County	177	n/a
16	Prince William County	177	-31
18	Fauquier County	174	-23
19	Giles County	172	-18
20	Frederick County	169	-32
21	Wythe County	166	-11
22	Prince Edward County	156	-34
23	Richmond city	133	+48
24	Bristol city	122	+83
25	Chesapeake city	120	+69
26	Norfolk city	117	+17
27	Newport News city	116	+81
28	Virginia Beach city	113	n/a
29	Lynchburg city	111	+76
30	Salem city	97	n/a
31	Roanoke city	96	+35
32	Northumberland County	49	+2
33	Charlottesville city	47	-4
34	King William County	45	-3
34	Rockingham County	45	-11
34	Winchester city	45	-3
37	Warren County	41	-4
38	Carroll County	37	-6
38	Culpeper County	37	-11
40	Fredericksburg city	36	-12
40	Wise County	36	-4
42	Tazewell County	33	-3

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. 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: 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), 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: highest daily AQI, Counties in Virginia by highest daily 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/highest-daily-air-quality-index/virginia-counties. 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), 1999. 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.

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), 1999 [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 (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: highest daily AQI: Counties in Virginia by highest daily 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/highest-daily-air-quality-index/virginia-counties. 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), 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/highest-daily-air-quality-index/virginia-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/virginia-counties.
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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Questions

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

Charles City County, with 223 in 1999, according to the U.S. Environmental Protection Agency.

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

Tazewell County, with 33 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: highest daily AQI. Retrieved 2026-10-12. 18 counties have no value for 1999 and are not ranked.