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

Median Air Quality Index (US EPA) in Buchanan County

Median Air Quality Index (US EPA) in Buchanan County was 46 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024. That is the 3rd highest of 21 counties in 2025.

2025, index46
Change on 2024+2
Rank3rd of 21Counties in Missouri ranked
Series high652008
Series low241995

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 Buchanan County, 1985 to 2025

20304050607019851991199720032009201520251985: 46 index1986: 43 index1987: 34 index1988: 41 index1989: 37 index1990: 34 index1991: 40 index1992: 33 index1993: 25 index1994: 29 index1995: 24 index1996: 25 index1997: 26 index1998: 31 index1999: 48 index2000: 56 index2001: 55 index2002: 56 index2003: 54 index2004: 53 index2005: 56 index2006: 54 index2007: 58 index2008: 65 index2009: 56 index2010: 54 index2011: 54 index2012: 53 index2013: 54 index2014: 52 index2015: 51 index2016: 44 index2017: 46 index2018: 47 index2019: 42 index2020: 42 index2021: 44 index2022: 42 index2023: 48 index2024: 44 index2025: 46 index2040608019851999201320251985: 46 index1986: 43 index1987: 34 index1988: 41 index1989: 37 index1990: 34 index1991: 40 index1992: 33 index1993: 25 index1994: 29 index1995: 24 index1996: 25 index1997: 26 index1998: 31 index1999: 48 index2000: 56 index2001: 55 index2002: 56 index2003: 54 index2004: 53 index2005: 56 index2006: 54 index2007: 58 index2008: 65 index2009: 56 index2010: 54 index2011: 54 index2012: 53 index2013: 54 index2014: 52 index2015: 51 index2016: 44 index2017: 46 index2018: 47 index2019: 42 index2020: 42 index2021: 44 index2022: 42 index2023: 48 index2024: 44 index2025: 46 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 41 values
Periodindex
202546
202444
202348
202242
202144
202042
201942
201847
201746
201644
201551
201452
201354
201253
201154
201054
200956
200865
200758
200654
200556
200453
200354
200256
200155
200056
199948
199831
199726
199625
199524
199429
199325
199233
199140
199034
198937
198841
198734
198643
198546

Buchanan County compared with nearby places

Andrew County: 40 indexBoone County: 37 indexBuchanan County: 46 indexCallaway County: 41 indexCass County: 41 indexCedar County: 39 indexClay County: 42 indexClinton County: 41 indexGreene County: 45 indexJackson County: 47 indexJasper County: 38 indexJefferson County: 42 indexLincoln County: 41 indexMonroe County: 35 indexPerry County: 41 indexSt. Charles County: 40 indexSte. Genevieve County: 41 indexSt. Louis County: 43 indexStoddard County: 21 indexTaney County: 28 indexSt. Louis city: 55 index
  • Under 38
  • 38 to 41
  • 41 to 43
  • 43 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Buchanan 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), Buchanan County, 1985 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), Buchanan County, 1985 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/buchanan-county-missouri. 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), Buchanan County, 1985 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/buchanan-county-missouri.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Buchanan County, 1985 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/buchanan-county-missouri (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), Buchanan County, 1985 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/buchanan-county-missouri. 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), Buchanan County, 1985 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/buchanan-county-missouri
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/buchanan-county-missouri.
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 Buchanan County?

Median Air Quality Index (US EPA) in Buchanan County was 46 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024. That is the 3rd highest of 21 counties in 2025.

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 Buchanan County?

65 in 2008, the highest value since 1985 in this series.

Related statistics for Buchanan County

All statistics for Buchanan County | Buchanan County in figures