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)

Floyd County had the highest share of days with good air quality (US EPA AQI) of 37 counties in 1998, at 100%. Hancock County had the lowest, at 36.9%. The median was 67.4%. Source: EPA.

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Highest100Floyd County
Lowest36.9Hancock County
Median67.437 counties

Map of counties, 1998

Bell County: 75.1 %Boone County: 61.7 %Boyd County: 80.3 %Bullitt County: 67.4 %Campbell County: 73.7 %Carter County: 40.4 %Christian County: 42.5 %Daviess County: 71.5 %Edmonson County: 52.8 %Fayette County: 73.7 %Floyd County: 100 %Graves County: 47.1 %Greenup County: 49 %Hancock County: 36.9 %Hardin County: 68.9 %Harlan County: 100 %Henderson County: 71.3 %Jefferson County: 60.8 %Jessamine County: 59.6 %Kenton County: 71 %Lawrence County: 79.2 %Livingston County: 45 %McCracken County: 65.8 %McLean County: 48.1 %Madison County: 98.2 %Marshall County: 92.9 %Morgan County: 62.7 %Oldham County: 55.4 %Perry County: 85.8 %Pike County: 62.4 %Pulaski County: 54.9 %Scott County: 70.4 %Simpson County: 68.2 %Trigg County: 59.4 %Warren County: 100 %Washington County: 61.1 %Whitley County: 100 %
  • Under 49
  • 49 to 61
  • 61 to 67
  • 67 to 72
  • 72 to 86
  • 86 and over
  • No data
%, 1998. 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, 1998

Floyd County: 100 %Floyd County100Harlan County: 100 %Harlan County100Warren County: 100 %Warren County100Whitley County: 100 %Whitley County100Madison County: 98.2 %Madison County98.2Marshall County: 92.9 %Marshall County92.9Perry County: 85.8 %Perry County85.8Boyd County: 80.3 %Boyd County80.3Lawrence County: 79.2 %Lawrence County79.2Bell County: 75.1 %Bell County75.1Campbell County: 73.7 %Campbell County73.7Fayette County: 73.7 %Fayette County73.7Daviess County: 71.5 %Daviess County71.5Henderson County: 71.3 %Henderson County71.3Kenton County: 71 %Kenton County71Scott County: 70.4 %Scott County70.4Hardin County: 68.9 %Hardin County68.9Simpson County: 68.2 %Simpson County68.2Bullitt County: 67.4 %Bullitt County67.4McCracken County: 65.8 %McCracken County65.8Morgan County: 62.7 %Morgan County62.7Pike County: 62.4 %Pike County62.4Boone County: 61.7 %Boone County61.7Washington County: 61.1 %Washington County61.1Jefferson County: 60.8 %Jefferson County60.8Jessamine County: 59.6 %Jessamine County59.6Trigg County: 59.4 %Trigg County59.4Oldham County: 55.4 %Oldham County55.4Pulaski County: 54.9 %Pulaski County54.9Edmonson County: 52.8 %Edmonson County52.8Greenup County: 49 %Greenup County49McLean County: 48.1 %McLean County48.1Graves County: 47.1 %Graves County47.1Livingston County: 45 %Livingston County45Christian County: 42.5 %Christian County42.5Carter County: 40.4 %Carter County40.4Hancock County: 36.9 %Hancock County36.9Floyd County: 100 %Floyd County100Harlan County: 100 %Harlan County100Warren County: 100 %Warren County100Whitley County: 100 %Whitley County100Madison County: 98.2 %Madison County98.2Marshall County: 92.9 %Marshall County92.9Perry County: 85.8 %Perry County85.8Boyd County: 80.3 %Boyd County80.3Lawrence County: 79.2 %Lawrence County79.2Bell County: 75.1 %Bell County75.1Campbell County: 73.7 %Campbell County73.7Fayette County: 73.7 %Fayette County73.7Daviess County: 71.5 %Daviess County71.5Henderson County: 71.3 %Henderson County71.3Kenton County: 71 %Kenton County71Scott County: 70.4 %Scott County70.4Hardin County: 68.9 %Hardin County68.9Simpson County: 68.2 %Simpson County68.2Bullitt County: 67.4 %Bullitt County67.4McCracken County: 65.8 %McCracken County65.8Morgan County: 62.7 %Morgan County62.7Pike County: 62.4 %Pike County62.4Boone County: 61.7 %Boone County61.7Washington County: 61.1 %Washington County61.1Jefferson County: 60.8 %Jefferson County60.8Jessamine County: 59.6 %Jessamine County59.6Trigg County: 59.4 %Trigg County59.4Oldham County: 55.4 %Oldham County55.4Pulaski County: 54.9 %Pulaski County54.9Edmonson County: 52.8 %Edmonson County52.8Greenup County: 49 %Greenup County49McLean County: 48.1 %McLean County48.1Graves County: 47.1 %Graves County47.1Livingston County: 45 %Livingston County45Christian County: 42.5 %Christian County42.5Carter County: 40.4 %Carter County40.4Hancock County: 36.9 %Hancock County36.9
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties1998 (%)Change on 1997
1Floyd County100+1.8 pts
1Harlan County100+1.6 pts
1Warren County1000 pts
1Whitley County100+1.7 pts
5Madison County98.2-1.8 pts
6Marshall County92.9-2 pts
7Perry County85.8-1.2 pts
8Boyd County80.3+0.3 pts
9Lawrence County79.2-12.7 pts
10Bell County75.1-3.3 pts
11Campbell County73.7-8.2 pts
11Fayette County73.7-4.1 pts
13Daviess County71.5-3.5 pts
14Henderson County71.3-5.4 pts
15Kenton County71-7.1 pts
16Scott County70.4-7.6 pts
17Hardin County68.9-14.9 pts
18Simpson County68.2-6.6 pts
19Bullitt County67.4-8.2 pts
20McCracken County65.8-16.7 pts
21Morgan County62.7-8 pts
22Pike County62.4-22.9 pts
23Boone County61.7-11.2 pts
24Washington County61.1-8.1 pts
25Jefferson County60.8-7.1 pts
26Jessamine County59.6-13.5 pts
27Trigg County59.4-10.5 pts
28Oldham County55.4-12.7 pts
29Pulaski County54.9-21.5 pts
30Edmonson County52.8-7.7 pts
31Greenup County49-32.6 pts
32McLean County48.1-16.4 pts
33Graves County47.1-26.5 pts
34Livingston County45-24.7 pts
35Christian County42.5-12.1 pts
36Carter County40.4n/a
37Hancock County36.9-24.3 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. 18 counties with data in other periods have no value for 1998 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), 1998) [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), 1998. 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=1998. 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), 1998. 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=1998.

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), 1998 [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=1998 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_kentucky_by_1998,
  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), 1998}},
  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=1998. 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), 1998
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=1998
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/kentucky-counties?period=1998.
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)?

Floyd County, with 100% in 1998, according to EPA.

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

Hancock County, with 36.9% in 1998.

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. 18 counties have no value for 1998 and are not ranked.

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

Counties in Kentucky: more rankings