Highest daily Air Quality Index (US EPA) in Loudon County

Highest daily Air Quality Index (US EPA) in Loudon County was 100 in 2025, according to the U.S. Environmental Protection Agency. That is unchanged from 2024.

2025, index100
Change on 20240
Series high1772007
Series low331995

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Highest daily Air Quality Index (US EPA) in Loudon County, 1990 to 2025

050100150200199019972006201020142018202220251990: 54 index1991: 46 index1995: 33 index1996: 174 index1997: 53 index2003: 98 index2004: 151 index2005: 156 index2006: 166 index2007: 177 index2008: 136 index2009: 136 index2010: 133 index2011: 147 index2012: 177 index2013: 80 index2014: 101 index2015: 100 index2016: 169 index2017: 87 index2018: 133 index2019: 93 index2020: 97 index2021: 90 index2022: 77 index2023: 107 index2024: 100 index2025: 100 index0501001502001990200820251990: 54 index1991: 46 index1995: 33 index1996: 174 index1997: 53 index2003: 98 index2004: 151 index2005: 156 index2006: 166 index2007: 177 index2008: 136 index2009: 136 index2010: 133 index2011: 147 index2012: 177 index2013: 80 index2014: 101 index2015: 100 index2016: 169 index2017: 87 index2018: 133 index2019: 93 index2020: 97 index2021: 90 index2022: 77 index2023: 107 index2024: 100 index2025: 100 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 28 values
Periodindex
2025100
2024100
2023107
202277
202190
202097
201993
2018133
201787
2016169
2015100
2014101
201380
2012177
2011147
2010133
2009136
2008136
2007177
2006166
2005156
2004151
200398
199753
1996174
199533
199146
199054

Loudon County compared with nearby places

Anderson County: 105 indexBlount County: 101 indexClaiborne County: 100 indexDavidson County: 136 indexDeKalb County: 84 indexDyer County: 72 indexHamilton County: 141 indexJefferson County: 93 indexKnox County: 156 indexLawrence County: 68 indexLoudon County: 100 indexMcMinn County: 71 indexMadison County: 96 indexMaury County: 74 indexMontgomery County: 130 indexPutnam County: 66 indexRoane County: 68 indexSevier County: 84 indexShelby County: 147 indexSullivan County: 90 indexSumner County: 119 indexWilliamson County: 100 indexWilson County: 77 index
  • Under 73
  • 73 to 89
  • 89 to 100
  • 100 to 130
  • 130 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Loudon County is outlined. Same source and period for every area shown. Source: U.S. Environmental Protection Agency. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

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.

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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 (Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025) [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, Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/highest-daily-air-quality-index/loudon-county-tennessee. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/highest-daily-air-quality-index/loudon-county-tennessee.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/loudon-county-tennessee (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025}},
  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/en/highest-daily-air-quality-index/loudon-county-tennessee. 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: Highest daily Air Quality Index (US EPA), Loudon County, 1990 to 2025
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/en/highest-daily-air-quality-index/loudon-county-tennessee
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/loudon-county-tennessee.
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

What is the highest daily Air Quality Index (US EPA) in Loudon County?

Highest daily Air Quality Index (US EPA) in Loudon County was 100 in 2025, according to the U.S. Environmental Protection Agency. That is unchanged from 2024.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: highest daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest highest daily Air Quality Index (US EPA) in Loudon County?

177 in 2007, the highest value since 1990 in this series.

Related statistics for Loudon County

All statistics for Loudon County | Loudon County in figures