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

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

Jefferson County had the highest median Air Quality Index (US EPA) of 30 counties in 1998, at 80. Dickson County had the lowest, at 15. The median was 44. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest80Jefferson County
Lowest15Dickson County
Median4430 counties

Map of counties, 1998

Anderson County: 58 indexBlount County: 54 indexBradley County: 27 indexClaiborne County: 44 indexCoffee County: 43 indexDavidson County: 42 indexDeKalb County: 42 indexDickson County: 15 indexHamblen County: 25 indexHamilton County: 58 indexHaywood County: 51 indexHenry County: 19 indexJefferson County: 80 indexKnox County: 45 indexLawrence County: 48 indexMcMinn County: 26 indexMadison County: 23 indexMaury County: 20 indexMontgomery County: 21 indexPutnam County: 67 indexRoane County: 29 indexRutherford County: 51 indexSevier County: 77 indexShelby County: 53 indexSullivan County: 44 indexSumner County: 43 indexUnion County: 39 indexWashington County: 22 indexWilliamson County: 61 indexWilson County: 47 index
  • Under 23
  • 23 to 36
  • 36 to 44
  • 44 to 49
  • 49 to 58
  • 58 and over
  • No data
index, 1998. 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, 1998

Jefferson County: 80 indexJefferson County80Sevier County: 77 indexSevier County77Putnam County: 67 indexPutnam County67Williamson County: 61 indexWilliamson County61Anderson County: 58 indexAnderson County58Hamilton County: 58 indexHamilton County58Blount County: 54 indexBlount County54Shelby County: 53 indexShelby County53Haywood County: 51 indexHaywood County51Rutherford County: 51 indexRutherford County51Lawrence County: 48 indexLawrence County48Wilson County: 47 indexWilson County47Knox County: 45 indexKnox County45Claiborne County: 44 indexClaiborne County44Sullivan County: 44 indexSullivan County44Coffee County: 43 indexCoffee County43Sumner County: 43 indexSumner County43Davidson County: 42 indexDavidson County42DeKalb County: 42 indexDeKalb County42Union County: 39 indexUnion County39Roane County: 29 indexRoane County29Bradley County: 27 indexBradley County27McMinn County: 26 indexMcMinn County26Hamblen County: 25 indexHamblen County25Madison County: 23 indexMadison County23Washington County: 22 indexWashington County22Montgomery County: 21 indexMontgomery County21Maury County: 20 indexMaury County20Henry County: 19 indexHenry County19Dickson County: 15 indexDickson County15Jefferson County: 80 indexJefferson County80Sevier County: 77 indexSevier County77Putnam County: 67 indexPutnam County67Williamson County: 61 indexWilliamson County61Anderson County: 58 indexAnderson County58Hamilton County: 58 indexHamilton County58Blount County: 54 indexBlount County54Shelby County: 53 indexShelby County53Haywood County: 51 indexHaywood County51Rutherford County: 51 indexRutherford County51Lawrence County: 48 indexLawrence County48Wilson County: 47 indexWilson County47Knox County: 45 indexKnox County45Claiborne County: 44 indexClaiborne County44Sullivan County: 44 indexSullivan County44Coffee County: 43 indexCoffee County43Sumner County: 43 indexSumner County43Davidson County: 42 indexDavidson County42DeKalb County: 42 indexDeKalb County42Union County: 39 indexUnion County39Roane County: 29 indexRoane County29Bradley County: 27 indexBradley County27McMinn County: 26 indexMcMinn County26Hamblen County: 25 indexHamblen County25Madison County: 23 indexMadison County23Washington County: 22 indexWashington County22Montgomery County: 21 indexMontgomery County21Maury County: 20 indexMaury County20Henry County: 19 indexHenry County19Dickson County: 15 indexDickson County15
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties1998
index		Change on 1997
1Jefferson County80+19
2Sevier County77+23
3Putnam County67+6
4Williamson County61+3
5Anderson County58+9
5Hamilton County58+13
7Blount County54+3
8Shelby County53+5
9Haywood County51+2
9Rutherford County51+1
11Lawrence County48+2
12Wilson County470
13Knox County45+6
14Claiborne County44+2
14Sullivan County440
16Coffee County43n/a
16Sumner County43-8
18Davidson County420
18DeKalb County420
20Union County39+1
21Roane County29+5
22Bradley County27-11
23McMinn County260
24Hamblen County25-15
25Madison County23+4
26Washington County220
27Montgomery County21+2
28Maury County20-1
29Henry County19-2
30Dickson County15-2

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. 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: 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 Tennessee by median Air Quality Index (US EPA), 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: median daily AQI, Counties in Tennessee by median Air Quality Index (US EPA), 1998. 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/tennessee-counties?period=1998. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Tennessee by median Air Quality Index (US EPA), 1998. 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/tennessee-counties?period=1998.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Tennessee by median Air Quality Index (US EPA), 1998 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/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: median daily AQI: Counties in Tennessee by median Air Quality Index (US EPA), 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/median-air-quality-index/tennessee-counties?period=1998. 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 Tennessee by median Air Quality Index (US EPA), 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/median-air-quality-index/tennessee-counties?period=1998
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/tennessee-counties?period=1998.
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 Tennessee 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)?

Jefferson County, with 80 in 1998, according to the U.S. Environmental Protection Agency.

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

Dickson County, with 15 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: median daily AQI. Retrieved 2026-10-12. 12 counties have no value for 1998 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Tennessee: more rankings