Smoke: keep one room clean
Shut the windows and run an air purifier sized for the room.
Wildfire smoke guide →Air quality in Kentucky, county by county
25 Kentucky counties have enough EPA monitor data to count bad-air days. Weighted by population, they averaged about 4 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 Kentucky county, weighted by population, almost no smoky days (fine particles over 35.4 µg/m³, mostly wildfire smoke) and about 1 high-ozone day a year at its worst spot (2018 to 2022). See every county on the map.
Every Kentucky county with monitors
Most bad-air days first. 17 have a full report. Compare with the worst and the cleanest counties in the US.
| County | Bad-air days a year | |
|---|---|---|
| Jefferson CountyOzone | 10.2 | |
| Campbell CountyFort ThomasOzone | 3.0 | |
| Boone CountyFlorenceOzoneparticles not measured | 2.8 | |
| McCracken CountyPaducahOzone | 2.6 | |
| Daviess CountyOwensboroOzone | 2.2 | |
| Oldham CountyLa GrangeOzoneparticles not measured | 2.2 | |
| Bullitt CountyMount WashingtonOzoneparticles not measured | 1.8 | |
| Perry CountyWinter particles | 1.8 | |
| Hancock CountyOzoneparticles not measured | 1.4 | |
| Livingston CountyOzoneparticles not measured | 1.4 | |
| Simpson CountyFranklinOzoneparticles not measured | 1.4 | |
| Hardin CountyElizabethtownOzone and particles | 1.2 | |
| Bell CountyMiddlesboroughSummer smoke | 1.2 | |
| Boyd CountyAshlandSummer smoke | 1.0 | |
| Christian CountyHopkinsvilleOzone | 1.0 | |
| Warren CountyBowling GreenSummer smoke | 1.0 | |
| Edmonson CountyOzone | 0.8 | |
| Fayette CountySummer smoke | 0.8 | |
| Jessamine CountyNicholasvilleOzone | 0.6 | |
| Pike CountyPikevilleWinter particles | 0.6 | |
| Pulaski CountySomersetSummer smoke | 0.6 | |
| Carter CountyRarely bad | 0.4 | |
| Washington CountyRarely badparticles not measured | 0.4 | |
| Greenup CountyRarely badparticles not measured | 0.0 | |
| Morgan CountyRarely badparticles not measured | 0.0 | |
| No Kentucky 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 Kentucky
Which county in Kentucky has the worst air?
Among Kentucky counties with EPA monitors, Jefferson County had the most bad-air days from 2021 to 2025: about 10 bad-air days a year with an AQI over 100. That's about 1 day in 36.
How often is the air bad in Kentucky?
Weighted by population, Kentucky counties with monitors averaged about 4 bad-air days a year from 2021 to 2025 with an AQI over 100, when children, older adults and people with asthma should cut back outdoors. That's about 1 day in 85.
Which county in Kentucky has the cleanest air?
2 of the 25 counties with enough monitor data had no bad-air days at all from 2021 to 2025, including Greenup County and Morgan County. Counties without monitors aren't ranked.
Where can I check today's air quality in Kentucky?
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.