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

Berkeley County had the highest share of days with good air quality (US EPA AQI) of 26 counties in 2005, at 87.4%. Greenville County had the lowest, at 17.3%. The median was 63.5%. Source: EPA.

Highest87.4Berkeley County

Lowest17.3Greenville County

Median63.526 counties

Map of counties, 2005

Under 32
32 to 63
63 to 65
65 to 75
75 and over
No data

%, 2005. 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, 2005

%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2005 (%)	Change on 2004
1	Berkeley County	87.4	+9.1 pts
2	Barnwell County	82.2	+2.3 pts
3	Colleton County	79.6	-1.4 pts
3	Williamsburg County	79.6	-2.8 pts
5	Cherokee County	77.7	-12.1 pts
6	Darlington County	74.5	-4.2 pts
7	Oconee County	71.9	-1.1 pts
8	York County	71.7	-2 pts
9	Union County	69.4	+1 pts
10	Pickens County	65.4	+0.3 pts
11	Edgefield County	65.1	-5.1 pts
12	Chesterfield County	64.3	-1.2 pts
13	Georgetown County	63.8	-1.9 pts
14	Aiken County	63.1	-8.6 pts
15	Abbeville County	63	-9.3 pts
15	Chester County	63	-9.8 pts
17	Lexington County	60.8	+1.9 pts
18	Anderson County	54	-12.2 pts
19	Beaufort County	34.4	-6 pts
20	Florence County	33	-0.9 pts
21	Horry County	31.9	-2.8 pts
22	Charleston County	25.8	-3.7 pts
23	Greenwood County	25.2	-1.8 pts
24	Spartanburg County	24	-3 pts
25	Richland County	20.8	-2.7 pts
26	Greenville County	17.3	-5.9 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. 2 counties with data in other periods have no value for 2005 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), 2005) [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), 2005. 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=2005. 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), 2005. 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=2005.

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), 2005 [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=2005 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_south_carolina_2005,
  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), 2005}},
  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=2005. 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), 2005
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=2005
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/south-carolina-counties?period=2005.
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)?

Berkeley County, with 87.4% in 2005, according to EPA.

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

Greenville County, with 17.3% in 2005.

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. 2 counties have no value for 2005 and are not ranked.