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

Spartanburg County had the highest highest daily Air Quality Index (US EPA) of 27 counties in 2003, at 172. Beaufort County had the lowest, at 80. The median was 129. Source: the U.S. Environmental Protection Agency.

Highest172Spartanburg County

Lowest80Beaufort County

Median12927 counties

Map of counties, 2003

Under 97
97 to 120
120 to 140
140 to 150
150 and over
No data

index, 2003. 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, 2003

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

Full ranking

Rank	Counties	2003 index	Change on 2002
1	Spartanburg County	172	-30
2	Richland County	169	-28
3	Cherokee County	154	-48
3	Darlington County	154	-31
5	Chesterfield County	151	-21
6	Abbeville County	150	-42
6	Anderson County	150	-45
8	Chester County	147	-45
8	Union County	147	-30
10	Pickens County	143	-44
11	Oconee County	140	-39
12	Charleston County	136	-23
13	Berkeley County	133	-18
14	York County	129	-61
15	Barnwell County	126	-38
15	Williamsburg County	126	-25
17	Aiken County	122	-63
18	Colleton County	119	-40
19	Greenville County	118	-18
20	Edgefield County	105	-85
21	Greenwood County	104	-5
22	Lexington County	95	-20
23	Florence County	92	-1
24	Orangeburg County	89	+1
25	Georgetown County	88	+1
26	Horry County	87	-79
27	Beaufort County	80	-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. 1 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: 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 South Carolina by highest daily Air Quality Index (US EPA), 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: highest daily AQI, Counties in South Carolina by highest daily Air Quality Index (US EPA), 2003. 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/south-carolina-counties?period=2003. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in South Carolina by highest daily Air Quality Index (US EPA), 2003. 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/south-carolina-counties?period=2003.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in South Carolina by highest daily Air Quality Index (US EPA), 2003 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/south-carolina-counties?period=2003 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_south_carolina_2003,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in South Carolina by highest daily Air Quality Index (US EPA), 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/highest-daily-air-quality-index/south-carolina-counties?period=2003. 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 South Carolina by highest daily Air Quality Index (US EPA), 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/highest-daily-air-quality-index/south-carolina-counties?period=2003
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/south-carolina-counties?period=2003.
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 South Carolina by highest daily Air Quality Index (US EPA) using official data, and cite the source.

rank_places {"indicator":"aqi_max","level":"province","within":"South Carolina","limit":10}
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Questions

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

Spartanburg County, with 172 in 2003, according to the U.S. Environmental Protection Agency.

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

Beaufort County, with 80 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: highest daily AQI. Retrieved 2026-10-12. 1 counties have no value for 2003 and are not ranked.