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), 2004

Henderson County had the highest share of days with good air quality (US EPA AQI) of 50 counties in 2004, at 100%. Davidson County had the lowest, at 15.6%. The median was 57.8%. Source: EPA.

Keep it in a collection in your library.
Highest100Henderson County
Lowest15.6Davidson County
Median57.850 counties

Map of counties, 2004

Alamance County: 30.2 %Alexander County: 81.3 %Avery County: 69 %Buncombe County: 37 %Cabarrus County: 24.8 %Caldwell County: 79.8 %Camden County: 75.6 %Carteret County: 88.5 %Caswell County: 57.3 %Catawba County: 21.4 %Chatham County: 55.9 %Cumberland County: 61.7 %Davidson County: 15.6 %Davie County: 68 %Duplin County: 36.3 %Durham County: 29.2 %Edgecombe County: 56.1 %Forsyth County: 27.6 %Franklin County: 68.2 %Gaston County: 24 %Graham County: 65.4 %Granville County: 61.2 %Guilford County: 28.7 %Haywood County: 46.4 %Henderson County: 100 %Jackson County: 57.8 %Johnston County: 72.8 %Lenoir County: 57.7 %Lincoln County: 68.2 %McDowell County: 28.4 %Macon County: 92.4 %Martin County: 61.5 %Mecklenburg County: 18.3 %Mitchell County: 31.4 %Montgomery County: 66.3 %New Hanover County: 70.4 %Onslow County: 41.9 %Orange County: 29.2 %Person County: 71.8 %Pitt County: 56.9 %Randolph County: 69.6 %Robeson County: 35.8 %Rockingham County: 72.4 %Rowan County: 59.2 %Swain County: 65 %Union County: 70.6 %Wake County: 30.6 %Watauga County: 43.2 %Wayne County: 27.9 %Yancey County: 76 %
  • Under 29
  • 29 to 39
  • 39 to 58
  • 58 to 67
  • 67 to 72
  • 72 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

Henderson County: 100 %Henderson County100Macon County: 92.4 %Macon County92.4Carteret County: 88.5 %Carteret County88.5Alexander County: 81.3 %Alexander County81.3Caldwell County: 79.8 %Caldwell County79.8Yancey County: 76 %Yancey County76Camden County: 75.6 %Camden County75.6Johnston County: 72.8 %Johnston County72.8Rockingham County: 72.4 %Rockingham County72.4Person County: 71.8 %Person County71.8Union County: 70.6 %Union County70.6New Hanover County: 70.4 %New Hanover County70.4Randolph County: 69.6 %Randolph County69.6Avery County: 69 %Avery County69Franklin County: 68.2 %Franklin County68.2Lincoln County: 68.2 %Lincoln County68.2Davie County: 68 %Davie County68Montgomery County: 66.3 %Montgomery County66.3Graham County: 65.4 %Graham County65.4Swain County: 65 %Swain County65Cumberland County: 61.7 %Cumberland County61.7Martin County: 61.5 %Martin County61.5Granville County: 61.2 %Granville County61.2Rowan County: 59.2 %Rowan County59.2Jackson County: 57.8 %Jackson County57.8Lenoir County: 57.7 %Lenoir County57.7Caswell County: 57.3 %Caswell County57.3Pitt County: 56.9 %Pitt County56.9Edgecombe County: 56.1 %Edgecombe County56.1Chatham County: 55.9 %Chatham County55.9Haywood County: 46.4 %Haywood County46.4Watauga County: 43.2 %Watauga County43.2Onslow County: 41.9 %Onslow County41.9Buncombe County: 37 %Buncombe County37Duplin County: 36.3 %Duplin County36.3Robeson County: 35.8 %Robeson County35.8Mitchell County: 31.4 %Mitchell County31.4Wake County: 30.6 %Wake County30.6Alamance County: 30.2 %Alamance County30.2Durham County: 29.2 %Durham County29.2Orange County: 29.2 %Orange County29.2Guilford County: 28.7 %Guilford County28.7McDowell County: 28.4 %McDowell County28.4Wayne County: 27.9 %Wayne County27.9Forsyth County: 27.6 %Forsyth County27.6Cabarrus County: 24.8 %Cabarrus County24.8Gaston County: 24 %Gaston County24Catawba County: 21.4 %Catawba County21.4Mecklenburg County: 18.3 %Mecklenburg County18.3Davidson County: 15.6 %Davidson County15.6Henderson County: 100 %Henderson County100Macon County: 92.4 %Macon County92.4Carteret County: 88.5 %Carteret County88.5Alexander County: 81.3 %Alexander County81.3Caldwell County: 79.8 %Caldwell County79.8Yancey County: 76 %Yancey County76Camden County: 75.6 %Camden County75.6Johnston County: 72.8 %Johnston County72.8Rockingham County: 72.4 %Rockingham County72.4Person County: 71.8 %Person County71.8Union County: 70.6 %Union County70.6New Hanover County: 70.4 %New Hanover County70.4Randolph County: 69.6 %Randolph County69.6Avery County: 69 %Avery County69Franklin County: 68.2 %Franklin County68.2Lincoln County: 68.2 %Lincoln County68.2Davie County: 68 %Davie County68Montgomery County: 66.3 %Montgomery County66.3Graham County: 65.4 %Graham County65.4Swain County: 65 %Swain County65Cumberland County: 61.7 %Cumberland County61.7Martin County: 61.5 %Martin County61.5Granville County: 61.2 %Granville County61.2Rowan County: 59.2 %Rowan County59.2Jackson County: 57.8 %Jackson County57.8Lenoir County: 57.7 %Lenoir County57.7Caswell County: 57.3 %Caswell County57.3Pitt County: 56.9 %Pitt County56.9Edgecombe County: 56.1 %Edgecombe County56.1Chatham County: 55.9 %Chatham County55.9Haywood County: 46.4 %Haywood County46.4Watauga County: 43.2 %Watauga County43.2Onslow County: 41.9 %Onslow County41.9Buncombe County: 37 %Buncombe County37Duplin County: 36.3 %Duplin County36.3Robeson County: 35.8 %Robeson County35.8Mitchell County: 31.4 %Mitchell County31.4Wake County: 30.6 %Wake County30.6Alamance County: 30.2 %Alamance County30.2Durham County: 29.2 %Durham County29.2Orange County: 29.2 %Orange County29.2Guilford County: 28.7 %Guilford County28.7McDowell County: 28.4 %McDowell County28.4Wayne County: 27.9 %Wayne County27.9Forsyth County: 27.6 %Forsyth County27.6Cabarrus County: 24.8 %Cabarrus County24.8Gaston County: 24 %Gaston County24Catawba County: 21.4 %Catawba County21.4Mecklenburg County: 18.3 %Mecklenburg County18.3Davidson County: 15.6 %Davidson County15.6
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2004 (%)Change on 2003
1Henderson County1000 pts
2Macon County92.4+1.4 pts
3Carteret County88.5+1.1 pts
4Alexander County81.3+18.4 pts
5Caldwell County79.8+16 pts
6Yancey County76+27.9 pts
7Camden County75.6+3.9 pts
8Johnston County72.8+1.8 pts
9Rockingham County72.4+6.7 pts
10Person County71.8+10.5 pts
11Union County70.6+3 pts
12New Hanover County70.4-4.5 pts
13Randolph County69.6-0.1 pts
14Avery County69+1.3 pts
15Franklin County68.2+5.7 pts
15Lincoln County68.2+13.7 pts
17Davie County68+14.7 pts
18Montgomery County66.3-1 pts
19Graham County65.4+13.7 pts
20Swain County65+5.3 pts
21Cumberland County61.7+1.9 pts
22Martin County61.5-10.2 pts
23Granville County61.2+4.6 pts
24Rowan County59.2+10.1 pts
25Jackson County57.8+19.2 pts
26Lenoir County57.7+1.4 pts
27Caswell County57.3+8.2 pts
28Pitt County56.9+2 pts
29Edgecombe County56.1+5.7 pts
30Chatham County55.9-3.6 pts
31Haywood County46.4+13.1 pts
32Watauga County43.2-3.3 pts
33Onslow County41.9+4.9 pts
34Buncombe County37-8.2 pts
35Duplin County36.3-26.2 pts
36Robeson County35.8+1.9 pts
37Mitchell County31.4-6 pts
38Wake County30.6+6.4 pts
39Alamance County30.2-3.1 pts
40Durham County29.2-3.3 pts
40Orange County29.2-4.1 pts
42Guilford County28.7+0.4 pts
43McDowell County28.4-4.9 pts
44Wayne County27.9-0.3 pts
45Forsyth County27.6+2.4 pts
46Cabarrus County24.8+1.7 pts
47Gaston County24-2.7 pts
48Catawba County21.4-0.4 pts
49Mecklenburg County18.3+1.3 pts
50Davidson County15.6-7.3 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. 12 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 North 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 North 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/north-carolina-counties. 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), 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/north-carolina-counties.

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), 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/north-carolina-counties (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_north_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 North 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/north-carolina-counties. 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), 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/north-carolina-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/north-carolina-counties.
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  -
Embed this chart

Paste this code into a web page or a blog post. The chart shows the latest figures as they are published, with the source and a link back to this page.

Sites that read oEmbed links, such as WordPress, can show the chart when you paste the link to this page.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

Rank Counties in North Carolina by share of days with good air quality (US EPA AQI) using official data, and cite the source.
rank_places {"indicator":"aqi_good_days_share","level":"province","within":"North Carolina","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=aqi_good_days_share&level=province&within=North%20Carolina&limit=10

Connect Claude, ChatGPT or Cursor in one step. The trial answers 25 calls a day without an account.

Questions

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

Henderson County, with 100% in 2004, according to EPA.

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

Davidson County, with 15.6% 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. 12 counties have no value for 2004 and are not ranked.

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

Counties in North Carolina: more rankings