# Counties in North Carolina by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2004

All 50 values come from U.S. Environmental Protection Agency for 2004, so the places are comparable. 12 counties have no value for that period and are not ranked.

- Indicator id: `aqi_unhealthy_sensitive_or_worse_days_share`
- Unit: %
- Definition: Days with a daily Air Quality Index above 100 (unhealthy for sensitive groups, unhealthy, very unhealthy or hazardous) 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; the counts are stored with each value.
- Source: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: days with an AQI above 100 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: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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.
- Web page: https://invokely.ai/rankings/unhealthy-air-quality-days-share/north-carolina-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Rowan County | 10.8 |
| 2 | Mecklenburg County | 9.3 |
| 3 | Granville County | 8.9 |
| 4 | Franklin County | 6.1 |
| 4 | Randolph County | 6.1 |
| 4 | Union County | 6.1 |
| 7 | Lincoln County | 5.2 |
| 8 | Davie County | 4.9 |
| 8 | Forsyth County | 4.9 |
| 8 | Wake County | 4.9 |
| 11 | Johnston County | 4.7 |
| 12 | Person County | 3.8 |
| 13 | Graham County | 3.3 |
| 13 | Rockingham County | 3.3 |
| 15 | Cumberland County | 3 |
| 15 | Haywood County | 3 |
| 17 | Pitt County | 2.7 |
| 18 | Camden County | 2.4 |
| 19 | Caswell County | 2.3 |
| 19 | Catawba County | 2.3 |
| 19 | Edgecombe County | 2.3 |
| 22 | Guilford County | 2.2 |
| 23 | Martin County | 2 |
| 24 | Alexander County | 1.9 |
| 24 | Durham County | 1.9 |
| 26 | McDowell County | 1.7 |
| 27 | Davidson County | 1.6 |
| 28 | Yancey County | 1.5 |
| 29 | Caldwell County | 1.4 |
| 30 | Jackson County | 1.2 |
| 30 | Lenoir County | 1.2 |
| 32 | Buncombe County | 1.1 |
| 32 | Montgomery County | 1.1 |
| 34 | Alamance County | 0.9 |
| 34 | New Hanover County | 0.9 |
| 36 | Avery County | 0.8 |
| 36 | Cabarrus County | 0.8 |
| 36 | Carteret County | 0.8 |
| 36 | Orange County | 0.8 |
| 36 | Robeson County | 0.8 |
| 36 | Wayne County | 0.8 |
| 42 | Chatham County | 0.4 |
| 43 | Macon County | 0.3 |
| 44 | Duplin County | 0 |
| 44 | Gaston County | 0 |
| 44 | Henderson County | 0 |
| 44 | Mitchell County | 0 |
| 44 | Onslow County | 0 |
| 44 | Swain County | 0 |
| 44 | Watauga County | 0 |