Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in Kentucky

Counties in Kentucky by share of days with good air quality (US EPA AQI)

Madison County had the highest share of days with good air quality (US EPA AQI) of 36 counties in 1997, at 100%. Christian County had the lowest, at 54.6%. The median was 77.3%. Source: EPA.

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Highest100Madison County
Lowest54.6Christian County
Median77.336 counties

Map of counties, 1997

Bell County: 78.4 %Boone County: 72.9 %Boyd County: 80 %Bullitt County: 75.6 %Campbell County: 81.9 %Christian County: 54.6 %Daviess County: 75 %Edmonson County: 60.5 %Fayette County: 77.8 %Floyd County: 98.2 %Graves County: 73.6 %Greenup County: 81.6 %Hancock County: 61.2 %Hardin County: 83.8 %Harlan County: 98.4 %Henderson County: 76.7 %Jefferson County: 67.9 %Jessamine County: 73.1 %Kenton County: 78.1 %Lawrence County: 91.9 %Livingston County: 69.7 %McCracken County: 82.5 %McLean County: 64.5 %Madison County: 100 %Marshall County: 94.9 %Morgan County: 70.7 %Oldham County: 68.1 %Perry County: 87 %Pike County: 85.3 %Pulaski County: 76.4 %Scott County: 78 %Simpson County: 74.8 %Trigg County: 69.9 %Warren County: 100 %Washington County: 69.2 %Whitley County: 98.3 %
  • Under 69
  • 69 to 73
  • 73 to 77
  • 77 to 82
  • 82 to 92
  • 92 and over
  • No data
%, 1997. 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, 1997

Madison County: 100 %Madison County100Warren County: 100 %Warren County100Harlan County: 98.4 %Harlan County98.4Whitley County: 98.3 %Whitley County98.3Floyd County: 98.2 %Floyd County98.2Marshall County: 94.9 %Marshall County94.9Lawrence County: 91.9 %Lawrence County91.9Perry County: 87 %Perry County87Pike County: 85.3 %Pike County85.3Hardin County: 83.8 %Hardin County83.8McCracken County: 82.5 %McCracken County82.5Campbell County: 81.9 %Campbell County81.9Greenup County: 81.6 %Greenup County81.6Boyd County: 80 %Boyd County80Bell County: 78.4 %Bell County78.4Kenton County: 78.1 %Kenton County78.1Scott County: 78 %Scott County78Fayette County: 77.8 %Fayette County77.8Henderson County: 76.7 %Henderson County76.7Pulaski County: 76.4 %Pulaski County76.4Bullitt County: 75.6 %Bullitt County75.6Daviess County: 75 %Daviess County75Simpson County: 74.8 %Simpson County74.8Graves County: 73.6 %Graves County73.6Jessamine County: 73.1 %Jessamine County73.1Boone County: 72.9 %Boone County72.9Morgan County: 70.7 %Morgan County70.7Trigg County: 69.9 %Trigg County69.9Livingston County: 69.7 %Livingston County69.7Washington County: 69.2 %Washington County69.2Oldham County: 68.1 %Oldham County68.1Jefferson County: 67.9 %Jefferson County67.9McLean County: 64.5 %McLean County64.5Hancock County: 61.2 %Hancock County61.2Edmonson County: 60.5 %Edmonson County60.5Christian County: 54.6 %Christian County54.6Madison County: 100 %Madison County100Warren County: 100 %Warren County100Harlan County: 98.4 %Harlan County98.4Whitley County: 98.3 %Whitley County98.3Floyd County: 98.2 %Floyd County98.2Marshall County: 94.9 %Marshall County94.9Lawrence County: 91.9 %Lawrence County91.9Perry County: 87 %Perry County87Pike County: 85.3 %Pike County85.3Hardin County: 83.8 %Hardin County83.8McCracken County: 82.5 %McCracken County82.5Campbell County: 81.9 %Campbell County81.9Greenup County: 81.6 %Greenup County81.6Boyd County: 80 %Boyd County80Bell County: 78.4 %Bell County78.4Kenton County: 78.1 %Kenton County78.1Scott County: 78 %Scott County78Fayette County: 77.8 %Fayette County77.8Henderson County: 76.7 %Henderson County76.7Pulaski County: 76.4 %Pulaski County76.4Bullitt County: 75.6 %Bullitt County75.6Daviess County: 75 %Daviess County75Simpson County: 74.8 %Simpson County74.8Graves County: 73.6 %Graves County73.6Jessamine County: 73.1 %Jessamine County73.1Boone County: 72.9 %Boone County72.9Morgan County: 70.7 %Morgan County70.7Trigg County: 69.9 %Trigg County69.9Livingston County: 69.7 %Livingston County69.7Washington County: 69.2 %Washington County69.2Oldham County: 68.1 %Oldham County68.1Jefferson County: 67.9 %Jefferson County67.9McLean County: 64.5 %McLean County64.5Hancock County: 61.2 %Hancock County61.2Edmonson County: 60.5 %Edmonson County60.5Christian County: 54.6 %Christian County54.6
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties1997 (%)Change on 1996
1Madison County100+1.7 pts
1Warren County1000 pts
3Harlan County98.4+0.1 pts
4Whitley County98.3-1.7 pts
5Floyd County98.20 pts
6Marshall County94.9-3.4 pts
7Lawrence County91.9+3.3 pts
8Perry County87-2 pts
9Pike County85.3+8.8 pts
10Hardin County83.8+17.8 pts
11McCracken County82.5-2.7 pts
12Campbell County81.9+1 pts
13Greenup County81.6+5.8 pts
14Boyd County80+3 pts
15Bell County78.4-8.5 pts
16Kenton County78.1+4.1 pts
17Scott County78+9 pts
18Fayette County77.8-3.1 pts
19Henderson County76.7+4.6 pts
20Pulaski County76.4-5.5 pts
21Bullitt County75.6-3 pts
22Daviess County75-4.5 pts
23Simpson County74.8+0.7 pts
24Graves County73.6-2.5 pts
25Jessamine County73.1-0.7 pts
26Boone County72.9-0.5 pts
27Morgan County70.7+2.2 pts
28Trigg County69.9+1.9 pts
29Livingston County69.7+1.2 pts
30Washington County69.2+9.3 pts
31Oldham County68.1-1.2 pts
32Jefferson County67.9-4 pts
33McLean County64.5+1.4 pts
34Hancock County61.2-4.3 pts
35Edmonson County60.5-2.1 pts
36Christian County54.6-15.7 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. 19 counties with data in other periods have no value for 1997 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 Kentucky by share of days with good air quality (US EPA AQI), 1997) [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 Kentucky by share of days with good air quality (US EPA AQI), 1997. 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/kentucky-counties?period=1997. 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 Kentucky by share of days with good air quality (US EPA AQI), 1997. 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/kentucky-counties?period=1997.

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 Kentucky by share of days with good air quality (US EPA AQI), 1997 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/kentucky-counties?period=1997 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_kentucky_by_1997,
  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 Kentucky by share of days with good air quality (US EPA AQI), 1997}},
  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/kentucky-counties?period=1997. 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 Kentucky by share of days with good air quality (US EPA AQI), 1997
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/kentucky-counties?period=1997
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/kentucky-counties?period=1997.
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  -
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Questions

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

Madison County, with 100% in 1997, according to EPA.

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

Christian County, with 54.6% in 1997.

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. 19 counties have no value for 1997 and are not ranked.

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

Counties in Kentucky: more rankings