Counties in Tennessee by highest daily Air Quality Index (US EPA)

Jefferson County had the highest highest daily Air Quality Index (US EPA) of 32 counties in 1996, at 207. Washington County had the lowest, at 48. The median was 159. Source: the U.S. Environmental Protection Agency.

Highest207Jefferson County

Lowest48Washington County

Median15932 counties

Map of counties, 1996

Under 55
55 to 80
80 to 160
160 to 170
170 to 190
190 and over
No data

index, 1996. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1996

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Rank	Counties	1996 index	Change on 1995
1	Jefferson County	207	-5
2	Knox County	206	+4
3	Sumner County	202	-1
4	Davidson County	200	+13
5	Giles County	197	+176
6	Hamilton County	195	-7
7	Shelby County	190	-15
8	Sullivan County	185	-7
9	Wilson County	179	0
10	Anderson County	174	-13
10	Haywood County	174	+10
10	Loudon County	174	+141
13	Sevier County	172	-31
13	Williamson County	172	-28
15	Blount County	161	-55
15	Humphreys County	161	n/a
17	DeKalb County	156	+9
17	Rutherford County	156	+20
19	Claiborne County	100	-79
19	Coffee County	100	-40
21	Bradley County	83	+6
22	McMinn County	79	+17
23	Henry County	72	-138
24	Union County	68	+11
25	Benton County	63	+38
26	Montgomery County	58	0
27	Dickson County	54	-125
27	Maury County	54	-1
27	Putnam County	54	-93
27	Roane County	54	-3
31	Madison County	48	-64
31	Washington County	48	-5

Other periods

About this ranking

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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. 10 counties with data in other periods have no value for 1996 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: highest 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: highest daily AQI (Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996) [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: highest daily AQI, Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/tennessee-counties?period=1996. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/tennessee-counties?period=1996.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/tennessee-counties?period=1996 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_tennessee_by_1996,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996}},
  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/highest-daily-air-quality-index/tennessee-counties?period=1996. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Counties in Tennessee by highest daily Air Quality Index (US EPA), 1996
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/highest-daily-air-quality-index/tennessee-counties?period=1996
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/tennessee-counties?period=1996.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. 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 highest daily Air Quality Index (US EPA)?

Jefferson County, with 207 in 1996, according to the U.S. Environmental Protection Agency.

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

Washington County, with 48 in 1996.

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: highest daily AQI. Retrieved 2026-10-12. 10 counties have no value for 1996 and are not ranked.