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

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

Harnett County had the highest share of days with good air quality (US EPA AQI) of 51 counties in 2000, at 100%. Catawba County had the lowest, at 12.7%. The median was 44.9%. Source: EPA.

Keep it in a collection in your library.
Highest100Harnett County
Lowest12.7Catawba County
Median44.951 counties

Map of counties, 2000

Alamance County: 17.3 %Alexander County: 44.5 %Avery County: 56.7 %Buncombe County: 44.6 %Cabarrus County: 16.5 %Caldwell County: 47.8 %Camden County: 74.8 %Carteret County: 76.8 %Caswell County: 37.8 %Catawba County: 12.7 %Chatham County: 47.7 %Cumberland County: 51.1 %Davidson County: 13.2 %Davie County: 43.2 %Duplin County: 47.1 %Durham County: 20.9 %Edgecombe County: 39.7 %Forsyth County: 17.2 %Franklin County: 54.9 %Gaston County: 13.2 %Granville County: 58.9 %Guilford County: 21.6 %Harnett County: 100 %Haywood County: 32.1 %Henderson County: 98.2 %Hyde County: 58.5 %Jackson County: 30 %Johnston County: 55.4 %Lenoir County: 45.2 %Lincoln County: 47.2 %McDowell County: 20.8 %Macon County: 75.5 %Martin County: 55.9 %Mecklenburg County: 13.4 %Mitchell County: 19.2 %Montgomery County: 52 %New Hanover County: 64.8 %Northampton County: 58.5 %Onslow County: 32.5 %Orange County: 49.2 %Pasquotank County: 41.2 %Person County: 53.3 %Pitt County: 41.3 %Robeson County: 24.4 %Rockingham County: 62 %Rowan County: 44.9 %Swain County: 49.8 %Union County: 65.7 %Wake County: 21.9 %Wayne County: 18.8 %Yancey County: 36.8 %
  • Under 20
  • 20 to 35
  • 35 to 45
  • 45 to 51
  • 51 to 59
  • 59 and over
  • No data
%, 2000. 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, 2000

Harnett County: 100 %Harnett County100Henderson County: 98.2 %Henderson County98.2Carteret County: 76.8 %Carteret County76.8Macon County: 75.5 %Macon County75.5Camden County: 74.8 %Camden County74.8Union County: 65.7 %Union County65.7New Hanover County: 64.8 %New Hanover County64.8Rockingham County: 62 %Rockingham County62Granville County: 58.9 %Granville County58.9Hyde County: 58.5 %Hyde County58.5Northampton County: 58.5 %Northampton County58.5Avery County: 56.7 %Avery County56.7Martin County: 55.9 %Martin County55.9Johnston County: 55.4 %Johnston County55.4Franklin County: 54.9 %Franklin County54.9Person County: 53.3 %Person County53.3Montgomery County: 52 %Montgomery County52Cumberland County: 51.1 %Cumberland County51.1Swain County: 49.8 %Swain County49.8Orange County: 49.2 %Orange County49.2Caldwell County: 47.8 %Caldwell County47.8Chatham County: 47.7 %Chatham County47.7Lincoln County: 47.2 %Lincoln County47.2Duplin County: 47.1 %Duplin County47.1Lenoir County: 45.2 %Lenoir County45.2Rowan County: 44.9 %Rowan County44.9Buncombe County: 44.6 %Buncombe County44.6Alexander County: 44.5 %Alexander County44.5Davie County: 43.2 %Davie County43.2Pitt County: 41.3 %Pitt County41.3Pasquotank County: 41.2 %Pasquotank County41.2Edgecombe County: 39.7 %Edgecombe County39.7Caswell County: 37.8 %Caswell County37.8Yancey County: 36.8 %Yancey County36.8Onslow County: 32.5 %Onslow County32.5Haywood County: 32.1 %Haywood County32.1Jackson County: 30 %Jackson County30Robeson County: 24.4 %Robeson County24.4Wake County: 21.9 %Wake County21.9Guilford County: 21.6 %Guilford County21.6Durham County: 20.9 %Durham County20.9McDowell County: 20.8 %McDowell County20.8Mitchell County: 19.2 %Mitchell County19.2Wayne County: 18.8 %Wayne County18.8Alamance County: 17.3 %Alamance County17.3Forsyth County: 17.2 %Forsyth County17.2Cabarrus County: 16.5 %Cabarrus County16.5Mecklenburg County: 13.4 %Mecklenburg County13.4Davidson County: 13.2 %Davidson County13.2Gaston County: 13.2 %Gaston County13.2Catawba County: 12.7 %Catawba County12.7Harnett County: 100 %Harnett County100Henderson County: 98.2 %Henderson County98.2Carteret County: 76.8 %Carteret County76.8Macon County: 75.5 %Macon County75.5Camden County: 74.8 %Camden County74.8Union County: 65.7 %Union County65.7New Hanover County: 64.8 %New Hanover County64.8Rockingham County: 62 %Rockingham County62Granville County: 58.9 %Granville County58.9Hyde County: 58.5 %Hyde County58.5Northampton County: 58.5 %Northampton County58.5Avery County: 56.7 %Avery County56.7Martin County: 55.9 %Martin County55.9Johnston County: 55.4 %Johnston County55.4Franklin County: 54.9 %Franklin County54.9Person County: 53.3 %Person County53.3Montgomery County: 52 %Montgomery County52Cumberland County: 51.1 %Cumberland County51.1Swain County: 49.8 %Swain County49.8Orange County: 49.2 %Orange County49.2Caldwell County: 47.8 %Caldwell County47.8Chatham County: 47.7 %Chatham County47.7Lincoln County: 47.2 %Lincoln County47.2Duplin County: 47.1 %Duplin County47.1Lenoir County: 45.2 %Lenoir County45.2Rowan County: 44.9 %Rowan County44.9Buncombe County: 44.6 %Buncombe County44.6Alexander County: 44.5 %Alexander County44.5Davie County: 43.2 %Davie County43.2Pitt County: 41.3 %Pitt County41.3Pasquotank County: 41.2 %Pasquotank County41.2Edgecombe County: 39.7 %Edgecombe County39.7Caswell County: 37.8 %Caswell County37.8Yancey County: 36.8 %Yancey County36.8Onslow County: 32.5 %Onslow County32.5Haywood County: 32.1 %Haywood County32.1Jackson County: 30 %Jackson County30Robeson County: 24.4 %Robeson County24.4Wake County: 21.9 %Wake County21.9Guilford County: 21.6 %Guilford County21.6Durham County: 20.9 %Durham County20.9McDowell County: 20.8 %McDowell County20.8Mitchell County: 19.2 %Mitchell County19.2Wayne County: 18.8 %Wayne County18.8Alamance County: 17.3 %Alamance County17.3Forsyth County: 17.2 %Forsyth County17.2Cabarrus County: 16.5 %Cabarrus County16.5Mecklenburg County: 13.4 %Mecklenburg County13.4Davidson County: 13.2 %Davidson County13.2Gaston County: 13.2 %Gaston County13.2Catawba County: 12.7 %Catawba County12.7
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2000 (%)Change on 1999
1Harnett County100+1.8 pts
2Henderson County98.2-1.8 pts
3Carteret County76.8+1 pts
4Macon County75.5+8.7 pts
5Camden County74.8+15.9 pts
6Union County65.7+15.2 pts
7New Hanover County64.8-6.3 pts
8Rockingham County62-3.7 pts
9Granville County58.9-4.6 pts
10Hyde County58.5n/a
10Northampton County58.5+3.7 pts
12Avery County56.7+3.3 pts
13Martin County55.9-7.8 pts
14Johnston County55.4+3.7 pts
15Franklin County54.9-10.2 pts
16Person County53.3+7.5 pts
17Montgomery County52-3.6 pts
18Cumberland County51.1-4.5 pts
19Swain County49.8+11.3 pts
20Orange County49.2-17.3 pts
21Caldwell County47.8+15.1 pts
22Chatham County47.7-5.9 pts
23Lincoln County47.2-20.3 pts
24Duplin County47.1-1.3 pts
25Lenoir County45.2-5.4 pts
26Rowan County44.9+12.2 pts
27Buncombe County44.6+7.9 pts
28Alexander County44.5-24.7 pts
29Davie County43.2+4.2 pts
30Pitt County41.3-9.9 pts
31Pasquotank County41.2-18.1 pts
32Edgecombe County39.7-13 pts
33Caswell County37.8-7.4 pts
34Yancey County36.8+13.9 pts
35Onslow County32.5-7.7 pts
36Haywood County32.1+9.6 pts
37Jackson County30-4.7 pts
38Robeson County24.4+4.6 pts
39Wake County21.9-0.7 pts
40Guilford County21.6-5.6 pts
41Durham County20.9-4.9 pts
42McDowell County20.8-4.2 pts
43Mitchell County19.2-9.2 pts
44Wayne County18.8-16.7 pts
45Alamance County17.3-0.9 pts
46Forsyth County17.2-4.4 pts
47Cabarrus County16.5-4.6 pts
48Mecklenburg County13.4+1.3 pts
49Davidson County13.2-10.2 pts
49Gaston County13.2-10.7 pts
51Catawba County12.7-8.5 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. 11 counties with data in other periods have no value for 2000 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 North Carolina by share of days with good air quality (US EPA AQI), 2000) [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 North Carolina by share of days with good air quality (US EPA AQI), 2000. 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/north-carolina-counties?period=2000. 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 North Carolina by share of days with good air quality (US EPA AQI), 2000. 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/north-carolina-counties?period=2000.

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 North Carolina by share of days with good air quality (US EPA AQI), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/north-carolina-counties?period=2000 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_north_carolina_2000,
  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 North Carolina by share of days with good air quality (US EPA AQI), 2000}},
  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/north-carolina-counties?period=2000. 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 North Carolina by share of days with good air quality (US EPA AQI), 2000
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/north-carolina-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/north-carolina-counties?period=2000.
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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Rank Counties in North Carolina by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

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

Harnett County, with 100% in 2000, according to EPA.

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

Catawba County, with 12.7% in 2000.

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. 11 counties have no value for 2000 and are not ranked.

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

Counties in North Carolina: more rankings