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

Highest daily Air Quality Index (US EPA) in Chaffee County was 108 in 2025, according to the U.S. Environmental Protection Agency. That is down 4 from 2024. That is the 14th highest of 30 counties in 2025.

2025, index108
Change on 2024-4
Series high1612018
Series low442017

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 Chaffee County, 2009 to 2025

2550751001251501752009201220152018202120252009: 100 index2010: 101 index2011: 112 index2012: 108 index2013: 126 index2014: 100 index2015: 108 index2016: 105 index2017: 44 index2018: 161 index2019: 108 index2020: 101 index2021: 119 index2022: 119 index2023: 115 index2024: 112 index2025: 108 index0501001502002009201520252009: 100 index2010: 101 index2011: 112 index2012: 108 index2013: 126 index2014: 100 index2015: 108 index2016: 105 index2017: 44 index2018: 161 index2019: 108 index2020: 101 index2021: 119 index2022: 119 index2023: 115 index2024: 112 index2025: 108 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 17 values
Periodindex
2025108
2024112
2023115
2022119
2021119
2020101
2019108
2018161
201744
2016105
2015108
2014100
2013126
2012108
2011112
2010101
2009100

Chaffee County compared with nearby places

Adams County: 112 indexAlamosa County: 76 indexArapahoe County: 101 indexArchuleta County: 115 indexBoulder County: 119 indexChaffee County: 108 indexClear Creek County: 100 indexDelta County: 103 indexDenver County: 115 indexDouglas County: 122 indexEl Paso County: 97 indexFremont County: 77 indexGarfield County: 131 indexGilpin County: 101 indexGrand County: 77 indexGunnison County: 115 indexJackson County: 56 indexJefferson County: 119 indexLa Plata County: 112 indexLarimer County: 119 indexMesa County: 97 indexMontezuma County: 101 indexPark County: 105 indexPitkin County: 154 indexProwers County: 652 indexPueblo County: 101 indexRoutt County: 87 indexSan Juan County: 57 indexSan Miguel County: 94 indexWeld County: 119 index
  • Under 85
  • 85 to 100
  • 100 to 120
  • 120 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Chaffee 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), Chaffee County, 2009 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), Chaffee County, 2009 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/chaffee-county-colorado. 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), Chaffee County, 2009 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/chaffee-county-colorado.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Chaffee County, 2009 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/chaffee-county-colorado (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), Chaffee County, 2009 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/chaffee-county-colorado. 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), Chaffee County, 2009 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/chaffee-county-colorado
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/chaffee-county-colorado.
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 Chaffee County?

Highest daily Air Quality Index (US EPA) in Chaffee County was 108 in 2025, according to the U.S. Environmental Protection Agency. That is down 4 from 2024. That is the 14th highest of 30 counties in 2025.

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 Chaffee County?

161 in 2018, the highest value since 2009 in this series.

Related statistics for Chaffee County

All statistics for Chaffee County | Chaffee County in figures