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)

Aiken County had the highest share of days with good air quality (US EPA AQI) of 27 counties in 2003, at 85.8%. Greenville County had the lowest, at 21.9%. The median was 68.3%. Source: EPA.

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Highest85.8Aiken County
Lowest21.9Greenville County
Median68.327 counties

Map of counties, 2003

Abbeville County: 68.3 %Aiken County: 85.8 %Anderson County: 58.4 %Barnwell County: 84.9 %Beaufort County: 49.6 %Berkeley County: 73.9 %Charleston County: 35.1 %Cherokee County: 79.7 %Chester County: 71.1 %Chesterfield County: 65.7 %Colleton County: 82.2 %Darlington County: 81.3 %Edgefield County: 73.7 %Florence County: 33.9 %Georgetown County: 65.1 %Greenville County: 21.9 %Greenwood County: 32.8 %Horry County: 35.3 %Lexington County: 68.6 %Oconee County: 68 %Orangeburg County: 82.3 %Pickens County: 58.6 %Richland County: 27.1 %Spartanburg County: 27.3 %Union County: 76 %Williamsburg County: 81.4 %York County: 74.6 %
  • Under 35
  • 35 to 65
  • 65 to 73
  • 73 to 81
  • 81 and over
  • No data
%, 2003. 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, 2003

Aiken County: 85.8 %Aiken County85.8Barnwell County: 84.9 %Barnwell County84.9Orangeburg County: 82.3 %Orangeburg County82.3Colleton County: 82.2 %Colleton County82.2Williamsburg County: 81.4 %Williamsburg County81.4Darlington County: 81.3 %Darlington County81.3Cherokee County: 79.7 %Cherokee County79.7Union County: 76 %Union County76York County: 74.6 %York County74.6Berkeley County: 73.9 %Berkeley County73.9Edgefield County: 73.7 %Edgefield County73.7Chester County: 71.1 %Chester County71.1Lexington County: 68.6 %Lexington County68.6Abbeville County: 68.3 %Abbeville County68.3Oconee County: 68 %Oconee County68Chesterfield County: 65.7 %Chesterfield County65.7Georgetown County: 65.1 %Georgetown County65.1Pickens County: 58.6 %Pickens County58.6Anderson County: 58.4 %Anderson County58.4Beaufort County: 49.6 %Beaufort County49.6Horry County: 35.3 %Horry County35.3Charleston County: 35.1 %Charleston County35.1Florence County: 33.9 %Florence County33.9Greenwood County: 32.8 %Greenwood County32.8Spartanburg County: 27.3 %Spartanburg County27.3Richland County: 27.1 %Richland County27.1Greenville County: 21.9 %Greenville County21.9Aiken County: 85.8 %Aiken County85.8Barnwell County: 84.9 %Barnwell County84.9Orangeburg County: 82.3 %Orangeburg County82.3Colleton County: 82.2 %Colleton County82.2Williamsburg County: 81.4 %Williamsburg County81.4Darlington County: 81.3 %Darlington County81.3Cherokee County: 79.7 %Cherokee County79.7Union County: 76 %Union County76York County: 74.6 %York County74.6Berkeley County: 73.9 %Berkeley County73.9Edgefield County: 73.7 %Edgefield County73.7Chester County: 71.1 %Chester County71.1Lexington County: 68.6 %Lexington County68.6Abbeville County: 68.3 %Abbeville County68.3Oconee County: 68 %Oconee County68Chesterfield County: 65.7 %Chesterfield County65.7Georgetown County: 65.1 %Georgetown County65.1Pickens County: 58.6 %Pickens County58.6Anderson County: 58.4 %Anderson County58.4Beaufort County: 49.6 %Beaufort County49.6Horry County: 35.3 %Horry County35.3Charleston County: 35.1 %Charleston County35.1Florence County: 33.9 %Florence County33.9Greenwood County: 32.8 %Greenwood County32.8Spartanburg County: 27.3 %Spartanburg County27.3Richland County: 27.1 %Richland County27.1Greenville County: 21.9 %Greenville County21.9
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2003 (%)Change on 2002
1Aiken County85.8+14.1 pts
2Barnwell County84.9+7.4 pts
3Orangeburg County82.3+25.9 pts
4Colleton County82.2+15.5 pts
5Williamsburg County81.4+9.9 pts
6Darlington County81.3+9.1 pts
7Cherokee County79.7+11.2 pts
8Union County76+18 pts
9York County74.6+16.4 pts
10Berkeley County73.9-4.1 pts
11Edgefield County73.7+12.7 pts
12Chester County71.1+17 pts
13Lexington County68.6+5.6 pts
14Abbeville County68.3+14.3 pts
15Oconee County68+6.9 pts
16Chesterfield County65.7+14.4 pts
17Georgetown County65.1-5 pts
18Pickens County58.6-0.5 pts
19Anderson County58.4+3.3 pts
20Beaufort County49.6+3.8 pts
21Horry County35.3-4.7 pts
22Charleston County35.1+3.9 pts
23Florence County33.9-5.2 pts
24Greenwood County32.8+2.4 pts
25Spartanburg County27.3-1.5 pts
26Richland County27.1+1.9 pts
27Greenville County21.90 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 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: 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), 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: 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), 2003. 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=2003. 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), 2003. 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=2003.

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), 2003 [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=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: 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), 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/good-air-quality-days-share/south-carolina-counties?period=2003. 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), 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/good-air-quality-days-share/south-carolina-counties?period=2003
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/south-carolina-counties?period=2003.
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)?

Aiken County, with 85.8% in 2003, according to EPA.

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

Greenville County, with 21.9% 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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 1 counties have no value for 2003 and are not ranked.

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

Counties in South Carolina: more rankings