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

Highest daily Air Quality Index (US EPA) in Monroe County was 165 in 2025, according to the U.S. Environmental Protection Agency. That is up 75 from 2024.

2025, index165
Change on 2024+75
Series high1732023
Series low332012

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 Monroe County, 2012 to 2025

05010015020020122013202120222023202420252012: 33 index2013: 44 index2021: 94 index2022: 132 index2023: 173 index2024: 90 index2025: 165 index0501001502002012202220252012: 33 index2013: 44 index2021: 94 index2022: 132 index2023: 173 index2024: 90 index2025: 165 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 7 values
Periodindex
2025165
202490
2023173
2022132
202194
201344
201233

Monroe County compared with nearby places

Ashland County: 188 indexBrown County: 175 indexColumbia County: 108 indexDane County: 170 indexDodge County: 171 indexDoor County: 108 indexEau Claire County: 174 indexFond du Lac County: 80 indexForest County: 182 indexGrant County: 167 indexJackson County: 172 indexJefferson County: 105 indexKenosha County: 167 indexKewaunee County: 105 indexLa Crosse County: 90 indexManitowoc County: 115 indexMarathon County: 168 indexMilwaukee County: 175 indexMonroe County: 165 indexOutagamie County: 172 indexOzaukee County: 167 indexRacine County: 122 indexRock County: 108 indexSauk County: 167 indexSheboygan County: 156 indexTaylor County: 97 indexVilas County: 105 indexWalworth County: 112 indexWaukesha County: 172 index
  • Under 110
  • 110 to 130
  • 130 to 170
  • 170 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Monroe 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), Monroe County, 2012 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), Monroe County, 2012 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/monroe-county-wisconsin. 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), Monroe County, 2012 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/monroe-county-wisconsin.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Monroe County, 2012 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/monroe-county-wisconsin (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), Monroe County, 2012 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/monroe-county-wisconsin. 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), Monroe County, 2012 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/monroe-county-wisconsin
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/monroe-county-wisconsin.
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 Monroe County?

Highest daily Air Quality Index (US EPA) in Monroe County was 165 in 2025, according to the U.S. Environmental Protection Agency. That is up 75 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 Monroe County?

173 in 2023, the highest value since 2012 in this series.

Related statistics for Monroe County

All statistics for Monroe County | Monroe County in figures