Smoke: keep one room clean
Shut the windows and run an air purifier sized for the room.
Wildfire smoke guide →Air quality in North Carolina, county by county
34 North Carolina counties have enough EPA monitor data to count bad-air days. Weighted by population, they averaged about 1 days a year from 2021 to 2025 when the air was unhealthy for sensitive groups or worse.
CDC's model, which estimates every county from monitors and satellites, gives the average North Carolina county, weighted by population, almost no smoky days (fine particles over 35.4 µg/m³, mostly wildfire smoke) and almost no high-ozone days a year at its worst spot (2018 to 2022). See every county on the map.
Every North Carolina county with monitors
Most bad-air days first. 19 have a full report. Compare with the worst and the cleanest counties in the US.
| County | Bad-air days a year | |
|---|---|---|
| Forsyth CountyWinston-SalemOzone and particles | 3.0 | |
| Mecklenburg CountyHuntersvilleOzone | 2.8 | |
| Graham CountyOzoneparticles not measured | 1.6 | |
| Haywood CountyWaynesvilleOzone | 1.4 | |
| Wake CountyRaleighSummer smoke | 1.4 | |
| Guilford CountyGreensboroOzone | 1.0 | |
| Cumberland CountyFayettevilleSummer smoke | 0.8 | |
| Catawba CountyHickorySmokeozone not measured | 0.6 | |
| Davidson CountyThomasvilleSmokeozone not measured | 0.6 | |
| Durham CountySummer smoke | 0.6 | |
| Granville CountyOzoneparticles not measured | 0.6 | |
| Montgomery CountySummer smoke | 0.6 | |
| New Hanover CountyWilmingtonSummer smoke | 0.6 | |
| Rowan CountySalisburySummer smoke | 0.6 | |
| Swain CountyWinter particles | 0.6 | |
| Carteret CountyMorehead CityRarely badparticles not measured | 0.4 | |
| Johnston CountyClaytonRarely bad | 0.4 | |
| Lenoir CountyKinstonRarely badparticles not measured | 0.4 | |
| Mitchell CountyRarely badozone not measured | 0.4 | |
| Pitt CountyGreenvilleRarely bad | 0.4 | |
| Union CountyIndian TrailRarely badparticles not measured | 0.4 | |
| Yancey CountyRarely badparticles not measured | 0.2 | |
| Alexander CountyRarely badparticles not measured | 0.2 | |
| Lincoln CountyLincolntonRarely badparticles not measured | 0.2 | |
| Northampton CountyRarely badozone not measured | 0.2 | |
| Person CountyRarely badparticles not measured | 0.2 | |
| Rockingham CountyEdenRarely badparticles not measured | 0.2 | |
| Avery CountyRarely bad | 0.0 | |
| Buncombe CountyAshevilleRarely bad | 0.0 | |
| Caldwell CountyLenoirRarely badparticles not measured | 0.0 | |
| Caswell CountyRarely badparticles not measured | 0.0 | |
| Edgecombe CountyRocky MountRarely bad | 0.0 | |
| Macon CountyRarely badparticles not measured | 0.0 | |
| Martin CountyRarely badparticles not measured | 0.0 | |
| No North Carolina county with a monitor matches “”. Counties without a monitor aren't listed; a neighbor's numbers are a fair guide, or find it on the map. | ||
Counties without a monitor aren't listed. Air doesn't stop at the county line, so a neighbor's numbers are a fair guide.
What helps on a bad-air day
Check AirNow for today's reading and tomorrow's forecast, then match the step to the pollutant.
Upgrade the furnace filter
MERV 13 catches far more smoke than thin fiberglass filters.
Furnace filters →Questions people ask about air quality in North Carolina
Which county in North Carolina has the worst air?
Among North Carolina counties with EPA monitors, Forsyth County had the most bad-air days from 2021 to 2025: about 3 bad-air days a year with an AQI over 100.
How often is the air bad in North Carolina?
Weighted by population, North Carolina counties with monitors averaged about 1 bad-air day a year from 2021 to 2025 with an AQI over 100, when children, older adults and people with asthma should cut back outdoors.
Which county in North Carolina has the cleanest air?
7 of the 34 counties with enough monitor data had no bad-air days at all from 2021 to 2025, including Buncombe County, Caldwell County and Edgecombe County. Counties without monitors aren't ranked.
Where can I check today's air quality in North Carolina?
AirNow, run by the EPA and its partners, shows current readings and forecasts by ZIP code, and its fire and smoke map adds smoke plumes and low-cost sensors.
Sources: EPA AirData county AQI summaries, 2021 to 2025; CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone, 2018 to 2022. Updated November 8, 2026.