Data / Median Air Quality Index (US EPA) / Sequoyah County

Median Air Quality Index (US EPA) in Sequoyah County

Median Air Quality Index (US EPA) in Sequoyah County was 42 in 2025, according to the U.S. Environmental Protection Agency. That is down 2 from 2024.

2025, index42
Change on 2024-2
Series high582005
Series low362015

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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Median Air Quality Index (US EPA) in Sequoyah County, 2004 to 2025

3540455055602004200820122016202020252004: 49 index2005: 58 index2006: 48 index2007: 40 index2008: 37 index2009: 37 index2010: 38 index2011: 44 index2012: 44 index2013: 39 index2014: 38 index2015: 36 index2016: 38 index2017: 38 index2018: 41 index2019: 41 index2020: 37 index2021: 41 index2022: 42 index2023: 46 index2024: 44 index2025: 42 index304050602004201220252004: 49 index2005: 58 index2006: 48 index2007: 40 index2008: 37 index2009: 37 index2010: 38 index2011: 44 index2012: 44 index2013: 39 index2014: 38 index2015: 36 index2016: 38 index2017: 38 index2018: 41 index2019: 41 index2020: 37 index2021: 41 index2022: 42 index2023: 46 index2024: 44 index2025: 42 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 22 values
Periodindex
202542
202444
202346
202242
202141
202037
201941
201841
201738
201638
201536
201438
201339
201244
201144
201038
200937
200837
200740
200648
200558
200449

Sequoyah County compared with nearby places

Adair County: 48 indexCanadian County: 43 indexCarter County: 32 indexCleveland County: 48 indexComanche County: 44 indexCreek County: 42 indexDewey County: 46 indexGrant County: 31 indexKay County: 37 indexKiowa County: 43 indexLove County: 44 indexMcClain County: 43 indexMayes County: 37 indexOklahoma County: 51 indexOsage County: 42 indexOttawa County: 49 indexPittsburg County: 48 indexSequoyah County: 42 indexTulsa County: 50 indexWashington County: 44 index
  • Under 41
  • 41 to 43
  • 43 to 44
  • 44 to 48
  • 48 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Sequoyah 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

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.

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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 (Median Air Quality Index (US EPA), Sequoyah County, 2004 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: median daily AQI, Median Air Quality Index (US EPA), Sequoyah County, 2004 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/median-air-quality-index/sequoyah-county-oklahoma. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Median Air Quality Index (US EPA), Sequoyah County, 2004 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/median-air-quality-index/sequoyah-county-oklahoma.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Sequoyah County, 2004 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/median-air-quality-index/sequoyah-county-oklahoma (Accessed: 12 October 2026).

BibTeX
@misc{environmental_median_air_quality_index_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Median Air Quality Index (US EPA), Sequoyah County, 2004 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/median-air-quality-index/sequoyah-county-oklahoma. 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: Median Air Quality Index (US EPA), Sequoyah County, 2004 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/median-air-quality-index/sequoyah-county-oklahoma
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/sequoyah-county-oklahoma.
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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Questions

What is the median Air Quality Index (US EPA) in Sequoyah County?

Median Air Quality Index (US EPA) in Sequoyah County was 42 in 2025, according to the U.S. Environmental Protection Agency. That is down 2 from 2024.

Where does this figure come from?

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

What was the highest median Air Quality Index (US EPA) in Sequoyah County?

58 in 2005, the highest value since 2004 in this series.

Related statistics for Sequoyah County

All statistics for Sequoyah County | Sequoyah County in figures