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)

Cherokee County had the highest share of days with good air quality (US EPA AQI) of 27 counties in 2004, at 89.8%. Greenville County had the lowest, at 23.2%. The median was 68.4%. Source: EPA.

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Highest89.8Cherokee County
Lowest23.2Greenville County
Median68.427 counties

Map of counties, 2004

Abbeville County: 72.3 %Aiken County: 71.7 %Anderson County: 66.2 %Barnwell County: 79.9 %Beaufort County: 40.4 %Berkeley County: 78.3 %Charleston County: 29.5 %Cherokee County: 89.8 %Chester County: 72.8 %Chesterfield County: 65.5 %Colleton County: 81 %Darlington County: 78.7 %Edgefield County: 70.2 %Florence County: 33.9 %Georgetown County: 65.7 %Greenville County: 23.2 %Greenwood County: 27 %Horry County: 34.7 %Lexington County: 58.9 %Oconee County: 73 %Orangeburg County: 78.5 %Pickens County: 65.1 %Richland County: 23.5 %Spartanburg County: 27 %Union County: 68.4 %Williamsburg County: 82.4 %York County: 73.7 %
  • Under 34
  • 34 to 66
  • 66 to 72
  • 72 to 78
  • 78 and over
  • No data
%, 2004. 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, 2004

Cherokee County: 89.8 %Cherokee County89.8Williamsburg County: 82.4 %Williamsburg County82.4Colleton County: 81 %Colleton County81Barnwell County: 79.9 %Barnwell County79.9Darlington County: 78.7 %Darlington County78.7Orangeburg County: 78.5 %Orangeburg County78.5Berkeley County: 78.3 %Berkeley County78.3York County: 73.7 %York County73.7Oconee County: 73 %Oconee County73Chester County: 72.8 %Chester County72.8Abbeville County: 72.3 %Abbeville County72.3Aiken County: 71.7 %Aiken County71.7Edgefield County: 70.2 %Edgefield County70.2Union County: 68.4 %Union County68.4Anderson County: 66.2 %Anderson County66.2Georgetown County: 65.7 %Georgetown County65.7Chesterfield County: 65.5 %Chesterfield County65.5Pickens County: 65.1 %Pickens County65.1Lexington County: 58.9 %Lexington County58.9Beaufort County: 40.4 %Beaufort County40.4Horry County: 34.7 %Horry County34.7Florence County: 33.9 %Florence County33.9Charleston County: 29.5 %Charleston County29.5Greenwood County: 27 %Greenwood County27Spartanburg County: 27 %Spartanburg County27Richland County: 23.5 %Richland County23.5Greenville County: 23.2 %Greenville County23.2Cherokee County: 89.8 %Cherokee County89.8Williamsburg County: 82.4 %Williamsburg County82.4Colleton County: 81 %Colleton County81Barnwell County: 79.9 %Barnwell County79.9Darlington County: 78.7 %Darlington County78.7Orangeburg County: 78.5 %Orangeburg County78.5Berkeley County: 78.3 %Berkeley County78.3York County: 73.7 %York County73.7Oconee County: 73 %Oconee County73Chester County: 72.8 %Chester County72.8Abbeville County: 72.3 %Abbeville County72.3Aiken County: 71.7 %Aiken County71.7Edgefield County: 70.2 %Edgefield County70.2Union County: 68.4 %Union County68.4Anderson County: 66.2 %Anderson County66.2Georgetown County: 65.7 %Georgetown County65.7Chesterfield County: 65.5 %Chesterfield County65.5Pickens County: 65.1 %Pickens County65.1Lexington County: 58.9 %Lexington County58.9Beaufort County: 40.4 %Beaufort County40.4Horry County: 34.7 %Horry County34.7Florence County: 33.9 %Florence County33.9Charleston County: 29.5 %Charleston County29.5Greenwood County: 27 %Greenwood County27Spartanburg County: 27 %Spartanburg County27Richland County: 23.5 %Richland County23.5Greenville County: 23.2 %Greenville County23.2
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2004 (%)Change on 2003
1Cherokee County89.8+10.1 pts
2Williamsburg County82.4+1 pts
3Colleton County81-1.2 pts
4Barnwell County79.9-5 pts
5Darlington County78.7-2.6 pts
6Orangeburg County78.5-3.8 pts
7Berkeley County78.3+4.4 pts
8York County73.7-0.9 pts
9Oconee County73+5 pts
10Chester County72.8+1.7 pts
11Abbeville County72.3+4 pts
12Aiken County71.7-14.1 pts
13Edgefield County70.2-3.5 pts
14Union County68.4-7.6 pts
15Anderson County66.2+7.8 pts
16Georgetown County65.7+0.6 pts
17Chesterfield County65.5-0.2 pts
18Pickens County65.1+6.5 pts
19Lexington County58.9-9.7 pts
20Beaufort County40.4-9.2 pts
21Horry County34.7-0.6 pts
22Florence County33.90 pts
23Charleston County29.5-5.6 pts
24Greenwood County27-5.8 pts
24Spartanburg County27-0.3 pts
26Richland County23.5-3.6 pts
27Greenville County23.2+1.3 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 2004 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), 2004) [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), 2004. 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=2004. 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), 2004. 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=2004.

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), 2004 [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=2004 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_south_carolina_2004,
  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), 2004}},
  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=2004. 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), 2004
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=2004
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/south-carolina-counties?period=2004.
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)?

Cherokee County, with 89.8% in 2004, according to EPA.

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

Greenville County, with 23.2% in 2004.

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 2004 and are not ranked.

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

Counties in South Carolina: more rankings