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

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

Dickson County had the highest share of days with good air quality (US EPA AQI) of 30 counties in 1998, at 100%. Jefferson County had the lowest, at 34.3%. The median was 62.2%. Source: EPA.

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Highest100Dickson County
Lowest34.3Jefferson County
Median62.230 counties

Map of counties, 1998

Anderson County: 44.2 %Blount County: 46.2 %Bradley County: 95.3 %Claiborne County: 63.4 %Coffee County: 69.8 %Davidson County: 67.4 %DeKalb County: 71.7 %Dickson County: 100 %Hamblen County: 94.8 %Hamilton County: 42.9 %Haywood County: 48.6 %Henry County: 100 %Jefferson County: 34.3 %Knox County: 57.3 %Lawrence County: 54.3 %McMinn County: 93.2 %Madison County: 100 %Maury County: 93.4 %Montgomery County: 100 %Putnam County: 34.6 %Roane County: 97 %Rutherford County: 48.8 %Sevier County: 34.7 %Shelby County: 47.1 %Sullivan County: 59.5 %Sumner County: 60.9 %Union County: 65.6 %Washington County: 100 %Williamson County: 43 %Wilson County: 57.4 %
  • Under 44
  • 44 to 52
  • 52 to 62
  • 62 to 79
  • 79 to 98
  • 98 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

Dickson County: 100 %Dickson County100Henry County: 100 %Henry County100Madison County: 100 %Madison County100Montgomery County: 100 %Montgomery County100Washington County: 100 %Washington County100Roane County: 97 %Roane County97Bradley County: 95.3 %Bradley County95.3Hamblen County: 94.8 %Hamblen County94.8Maury County: 93.4 %Maury County93.4McMinn County: 93.2 %McMinn County93.2DeKalb County: 71.7 %DeKalb County71.7Coffee County: 69.8 %Coffee County69.8Davidson County: 67.4 %Davidson County67.4Union County: 65.6 %Union County65.6Claiborne County: 63.4 %Claiborne County63.4Sumner County: 60.9 %Sumner County60.9Sullivan County: 59.5 %Sullivan County59.5Wilson County: 57.4 %Wilson County57.4Knox County: 57.3 %Knox County57.3Lawrence County: 54.3 %Lawrence County54.3Rutherford County: 48.8 %Rutherford County48.8Haywood County: 48.6 %Haywood County48.6Shelby County: 47.1 %Shelby County47.1Blount County: 46.2 %Blount County46.2Anderson County: 44.2 %Anderson County44.2Williamson County: 43 %Williamson County43Hamilton County: 42.9 %Hamilton County42.9Sevier County: 34.7 %Sevier County34.7Putnam County: 34.6 %Putnam County34.6Jefferson County: 34.3 %Jefferson County34.3Dickson County: 100 %Dickson County100Henry County: 100 %Henry County100Madison County: 100 %Madison County100Montgomery County: 100 %Montgomery County100Washington County: 100 %Washington County100Roane County: 97 %Roane County97Bradley County: 95.3 %Bradley County95.3Hamblen County: 94.8 %Hamblen County94.8Maury County: 93.4 %Maury County93.4McMinn County: 93.2 %McMinn County93.2DeKalb County: 71.7 %DeKalb County71.7Coffee County: 69.8 %Coffee County69.8Davidson County: 67.4 %Davidson County67.4Union County: 65.6 %Union County65.6Claiborne County: 63.4 %Claiborne County63.4Sumner County: 60.9 %Sumner County60.9Sullivan County: 59.5 %Sullivan County59.5Wilson County: 57.4 %Wilson County57.4Knox County: 57.3 %Knox County57.3Lawrence County: 54.3 %Lawrence County54.3Rutherford County: 48.8 %Rutherford County48.8Haywood County: 48.6 %Haywood County48.6Shelby County: 47.1 %Shelby County47.1Blount County: 46.2 %Blount County46.2Anderson County: 44.2 %Anderson County44.2Williamson County: 43 %Williamson County43Hamilton County: 42.9 %Hamilton County42.9Sevier County: 34.7 %Sevier County34.7Putnam County: 34.6 %Putnam County34.6Jefferson County: 34.3 %Jefferson County34.3
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties1998 (%)Change on 1997
1Dickson County1000 pts
1Henry County100+1.6 pts
1Madison County1000 pts
1Montgomery County1000 pts
1Washington County100+1.8 pts
6Roane County97+6.4 pts
7Bradley County95.3+24.2 pts
8Hamblen County94.8+26.9 pts
9Maury County93.4-5 pts
10McMinn County93.2-2.9 pts
11DeKalb County71.7+0.5 pts
12Coffee County69.8n/a
13Davidson County67.40 pts
14Union County65.6-2.9 pts
15Claiborne County63.4-4.3 pts
16Sumner County60.9+10.9 pts
17Sullivan County59.5-4.6 pts
18Wilson County57.4+2.5 pts
19Knox County57.3-6.8 pts
20Lawrence County54.3-4.7 pts
21Rutherford County48.8-1.4 pts
22Haywood County48.6-4.1 pts
23Shelby County47.1-8.2 pts
24Blount County46.2-1.4 pts
25Anderson County44.2-8.7 pts
26Williamson County43-2 pts
27Hamilton County42.9-20.6 pts
28Sevier County34.7-10.8 pts
29Putnam County34.6-5.6 pts
30Jefferson County34.3-5 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. 12 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 Tennessee 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 Tennessee 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/tennessee-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 Tennessee 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/tennessee-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 Tennessee 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/tennessee-counties?period=1998 (Accessed: 12 October 2026).

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

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

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

Jefferson County, with 34.3% 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. 12 counties have no value for 1998 and are not ranked.

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

Counties in Tennessee: more rankings