Data / Rankings / Median Air Quality Index (US EPA) / Counties in Kentucky

Counties in Kentucky by median Air Quality Index (US EPA)

Hancock County had the highest median Air Quality Index (US EPA) of 37 counties in 1995, at 51. Warren County had the lowest, at 19. The median was 43. Source: the U.S. Environmental Protection Agency.

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Highest51Hancock County
Lowest19Warren County
Median4337 counties

Map of counties, 1995

Bell County: 35 indexBoone County: 44 indexBoyd County: 40 indexBullitt County: 36 indexCampbell County: 38 indexCarter County: 27 indexChristian County: 47 indexDaviess County: 35 indexEdmonson County: 45 indexFayette County: 41 indexFloyd County: 23 indexGraves County: 44 indexGreenup County: 46 indexHancock County: 51 indexHardin County: 48 indexHarlan County: 30 indexHenderson County: 41 indexJefferson County: 43 indexJessamine County: 45 indexKenton County: 44 indexLawrence County: 41 indexLivingston County: 46 indexMcCracken County: 35 indexMcLean County: 50 indexMadison County: 23 indexMarshall County: 22 indexMorgan County: 48 indexOldham County: 46 indexPerry County: 41 indexPike County: 45 indexPulaski County: 46 indexScott County: 47 indexSimpson County: 41 indexTrigg County: 44 indexWarren County: 19 indexWashington County: 49 indexWhitley County: 20 index
  • Under 30
  • 30 to 40
  • 40 to 43
  • 43 to 45
  • 45 to 47
  • 47 and over
  • No data
index, 1995. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1995

Hancock County: 51 indexHancock County51McLean County: 50 indexMcLean County50Washington County: 49 indexWashington County49Hardin County: 48 indexHardin County48Morgan County: 48 indexMorgan County48Christian County: 47 indexChristian County47Scott County: 47 indexScott County47Greenup County: 46 indexGreenup County46Livingston County: 46 indexLivingston County46Oldham County: 46 indexOldham County46Pulaski County: 46 indexPulaski County46Edmonson County: 45 indexEdmonson County45Jessamine County: 45 indexJessamine County45Pike County: 45 indexPike County45Boone County: 44 indexBoone County44Graves County: 44 indexGraves County44Kenton County: 44 indexKenton County44Trigg County: 44 indexTrigg County44Jefferson County: 43 indexJefferson County43Fayette County: 41 indexFayette County41Henderson County: 41 indexHenderson County41Lawrence County: 41 indexLawrence County41Perry County: 41 indexPerry County41Simpson County: 41 indexSimpson County41Boyd County: 40 indexBoyd County40Campbell County: 38 indexCampbell County38Bullitt County: 36 indexBullitt County36Bell County: 35 indexBell County35Daviess County: 35 indexDaviess County35McCracken County: 35 indexMcCracken County35Harlan County: 30 indexHarlan County30Carter County: 27 indexCarter County27Floyd County: 23 indexFloyd County23Madison County: 23 indexMadison County23Marshall County: 22 indexMarshall County22Whitley County: 20 indexWhitley County20Warren County: 19 indexWarren County19Hancock County: 51 indexHancock County51McLean County: 50 indexMcLean County50Washington County: 49 indexWashington County49Hardin County: 48 indexHardin County48Morgan County: 48 indexMorgan County48Christian County: 47 indexChristian County47Scott County: 47 indexScott County47Greenup County: 46 indexGreenup County46Livingston County: 46 indexLivingston County46Oldham County: 46 indexOldham County46Pulaski County: 46 indexPulaski County46Edmonson County: 45 indexEdmonson County45Jessamine County: 45 indexJessamine County45Pike County: 45 indexPike County45Boone County: 44 indexBoone County44Graves County: 44 indexGraves County44Kenton County: 44 indexKenton County44Trigg County: 44 indexTrigg County44Jefferson County: 43 indexJefferson County43Fayette County: 41 indexFayette County41Henderson County: 41 indexHenderson County41Lawrence County: 41 indexLawrence County41Perry County: 41 indexPerry County41Simpson County: 41 indexSimpson County41Boyd County: 40 indexBoyd County40Campbell County: 38 indexCampbell County38Bullitt County: 36 indexBullitt County36Bell County: 35 indexBell County35Daviess County: 35 indexDaviess County35McCracken County: 35 indexMcCracken County35Harlan County: 30 indexHarlan County30Carter County: 27 indexCarter County27Floyd County: 23 indexFloyd County23Madison County: 23 indexMadison County23Marshall County: 22 indexMarshall County22Whitley County: 20 indexWhitley County20Warren County: 19 indexWarren County19
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties1995
index		Change on 1994
1Hancock County51+5
2McLean County50+2
3Washington County49+5
4Hardin County48+4
4Morgan County48+4
6Christian County47-7
6Scott County47-3
8Greenup County46+1
8Livingston County460
8Oldham County46+1
8Pulaski County46+4
12Edmonson County45+2
12Jessamine County45+1
12Pike County45+2
15Boone County44-2
15Graves County44+3
15Kenton County44+2
15Trigg County44+1
19Jefferson County43-5
20Fayette County410
20Henderson County41+2
20Lawrence County41+2
20Perry County41+1
20Simpson County41+3
25Boyd County40-1
26Campbell County38-2
27Bullitt County360
28Bell County35-3
28Daviess County35-1
28McCracken County35-1
31Harlan County30+1
32Carter County27+3
33Floyd County23-1
33Madison County23-1
35Marshall County22-2
36Whitley County20-3
37Warren County19+1

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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. 18 counties with data in other periods have no value for 1995 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: median daily AQI. 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: median daily AQI (Counties in Kentucky by median Air Quality Index (US EPA), 1995) [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: median daily AQI, Counties in Kentucky by median Air Quality Index (US EPA), 1995. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/kentucky-counties?period=1995. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Kentucky by median Air Quality Index (US EPA), 1995. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/kentucky-counties?period=1995.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Kentucky by median Air Quality Index (US EPA), 1995 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/kentucky-counties?period=1995 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_kentucky_by_1995,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Kentucky by median Air Quality Index (US EPA), 1995}},
  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/median-air-quality-index/kentucky-counties?period=1995. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. 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: median daily AQI: Counties in Kentucky by median Air Quality Index (US EPA), 1995
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/median-air-quality-index/kentucky-counties?period=1995
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/kentucky-counties?period=1995.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Kentucky by median Air Quality Index (US EPA) using official data, and cite the source.
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Questions

Which county has the highest median Air Quality Index (US EPA)?

Hancock County, with 51 in 1995, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Warren County, with 19 in 1995.

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: median daily AQI. Retrieved 2026-10-12. 18 counties have no value for 1995 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Kentucky: more rankings