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

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

Fairfield County had the highest share of days with good air quality (US EPA AQI) of 27 counties in 2001, at 100%. Greenville County had the lowest, at 21.4%. The median was 54.2%. Source: EPA.

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Highest100Fairfield County
Lowest21.4Greenville County
Median54.227 counties

Map of counties, 2001

Abbeville County: 53 %Aiken County: 70.1 %Anderson County: 53.7 %Barnwell County: 77.7 %Beaufort County: 37.5 %Berkeley County: 82.9 %Charleston County: 28.2 %Cherokee County: 66.1 %Chester County: 53.6 %Chesterfield County: 31.9 %Colleton County: 66.5 %Darlington County: 67.8 %Edgefield County: 63.6 %Fairfield County: 100 %Florence County: 29.6 %Georgetown County: 74.8 %Greenville County: 21.4 %Greenwood County: 25.4 %Horry County: 36 %Lexington County: 55.4 %Oconee County: 63.6 %Pickens County: 54.2 %Richland County: 42.5 %Spartanburg County: 24.7 %Union County: 68.2 %Williamsburg County: 83.9 %York County: 53.7 %
  • Under 33
  • 33 to 54
  • 54 to 64
  • 64 to 70
  • 70 and over
  • No data
%, 2001. 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, 2001

Fairfield County: 100 %Fairfield County100Williamsburg County: 83.9 %Williamsburg County83.9Berkeley County: 82.9 %Berkeley County82.9Barnwell County: 77.7 %Barnwell County77.7Georgetown County: 74.8 %Georgetown County74.8Aiken County: 70.1 %Aiken County70.1Union County: 68.2 %Union County68.2Darlington County: 67.8 %Darlington County67.8Colleton County: 66.5 %Colleton County66.5Cherokee County: 66.1 %Cherokee County66.1Edgefield County: 63.6 %Edgefield County63.6Oconee County: 63.6 %Oconee County63.6Lexington County: 55.4 %Lexington County55.4Pickens County: 54.2 %Pickens County54.2Anderson County: 53.7 %Anderson County53.7York County: 53.7 %York County53.7Chester County: 53.6 %Chester County53.6Abbeville County: 53 %Abbeville County53Richland County: 42.5 %Richland County42.5Beaufort County: 37.5 %Beaufort County37.5Horry County: 36 %Horry County36Chesterfield County: 31.9 %Chesterfield County31.9Florence County: 29.6 %Florence County29.6Charleston County: 28.2 %Charleston County28.2Greenwood County: 25.4 %Greenwood County25.4Spartanburg County: 24.7 %Spartanburg County24.7Greenville County: 21.4 %Greenville County21.4Fairfield County: 100 %Fairfield County100Williamsburg County: 83.9 %Williamsburg County83.9Berkeley County: 82.9 %Berkeley County82.9Barnwell County: 77.7 %Barnwell County77.7Georgetown County: 74.8 %Georgetown County74.8Aiken County: 70.1 %Aiken County70.1Union County: 68.2 %Union County68.2Darlington County: 67.8 %Darlington County67.8Colleton County: 66.5 %Colleton County66.5Cherokee County: 66.1 %Cherokee County66.1Edgefield County: 63.6 %Edgefield County63.6Oconee County: 63.6 %Oconee County63.6Lexington County: 55.4 %Lexington County55.4Pickens County: 54.2 %Pickens County54.2Anderson County: 53.7 %Anderson County53.7York County: 53.7 %York County53.7Chester County: 53.6 %Chester County53.6Abbeville County: 53 %Abbeville County53Richland County: 42.5 %Richland County42.5Beaufort County: 37.5 %Beaufort County37.5Horry County: 36 %Horry County36Chesterfield County: 31.9 %Chesterfield County31.9Florence County: 29.6 %Florence County29.6Charleston County: 28.2 %Charleston County28.2Greenwood County: 25.4 %Greenwood County25.4Spartanburg County: 24.7 %Spartanburg County24.7Greenville County: 21.4 %Greenville County21.4
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2001 (%)Change on 2000
1Fairfield County100+1.7 pts
2Williamsburg County83.9+18.9 pts
3Berkeley County82.9+7.6 pts
4Barnwell County77.7+11.2 pts
5Georgetown County74.8+4.1 pts
6Aiken County70.1+7.4 pts
7Union County68.2-0.6 pts
8Darlington County67.8+1.4 pts
9Colleton County66.5+11.5 pts
10Cherokee County66.1+11.4 pts
11Edgefield County63.6+10.5 pts
11Oconee County63.6+6 pts
13Lexington County55.4+7.7 pts
14Pickens County54.2+14 pts
15Anderson County53.7+0.5 pts
15York County53.7+8.5 pts
17Chester County53.6+0.3 pts
18Abbeville County53+8.3 pts
19Richland County42.5+4 pts
20Beaufort County37.5+4.8 pts
21Horry County36-4 pts
22Chesterfield County31.9+8.6 pts
23Florence County29.6+5 pts
24Charleston County28.2+5.8 pts
25Greenwood County25.4+11.7 pts
26Spartanburg County24.7+4.5 pts
27Greenville County21.4+2.3 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. 1 counties with data in other periods have no value for 2001 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 South Carolina by share of days with good air quality (US EPA AQI), 2001) [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 South Carolina by share of days with good air quality (US EPA AQI), 2001. 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/south-carolina-counties?period=2001. 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 South Carolina by share of days with good air quality (US EPA AQI), 2001. 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/south-carolina-counties?period=2001.

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 South Carolina by share of days with good air quality (US EPA AQI), 2001 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/south-carolina-counties?period=2001 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_south_carolina_2001,
  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 South Carolina by share of days with good air quality (US EPA AQI), 2001}},
  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/south-carolina-counties?period=2001. 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 South Carolina by share of days with good air quality (US EPA AQI), 2001
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/south-carolina-counties?period=2001
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/south-carolina-counties?period=2001.
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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Questions

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

Fairfield County, with 100% in 2001, according to EPA.

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

Greenville County, with 21.4% in 2001.

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. 1 counties have no value for 2001 and are not ranked.

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

Counties in South Carolina: more rankings