Median Air Quality Index (US EPA) in Hendricks County

Median Air Quality Index (US EPA) in Hendricks County was 35 in 2025, according to the U.S. Environmental Protection Agency. That is unchanged from 2024.

2025, index35
Change on 20240
Series high641998
Series low292006

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 Hendricks County, 1998 to 2025

203040506070199820022006201020142018202220251998: 64 index1999: 62 index2000: 60 index2001: 48 index2002: 50 index2003: 41 index2004: 36 index2005: 34 index2006: 29 index2007: 32 index2008: 30 index2009: 37 index2010: 41 index2011: 40 index2012: 45 index2013: 38 index2014: 36 index2015: 35 index2016: 40 index2017: 38 index2018: 33 index2019: 34 index2020: 32 index2021: 33 index2022: 34 index2023: 37 index2024: 35 index2025: 35 index2030405060701998200820251998: 64 index1999: 62 index2000: 60 index2001: 48 index2002: 50 index2003: 41 index2004: 36 index2005: 34 index2006: 29 index2007: 32 index2008: 30 index2009: 37 index2010: 41 index2011: 40 index2012: 45 index2013: 38 index2014: 36 index2015: 35 index2016: 40 index2017: 38 index2018: 33 index2019: 34 index2020: 32 index2021: 33 index2022: 34 index2023: 37 index2024: 35 index2025: 35 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 28 values
Periodindex
202535
202435
202337
202234
202133
202032
201934
201833
201738
201640
201535
201436
201338
201245
201140
201041
200937
200830
200732
200629
200534
200436
200341
200250
200148
200060
199962
199864

Hendricks County compared with nearby places

Allen County: 44 indexBartholomew County: 43 indexBoone County: 35 indexBrown County: 34 indexCarroll County: 35 indexClark County: 46 indexDelaware County: 43 indexDubois County: 39 indexElkhart County: 43 indexFloyd County: 44 indexGreene County: 42 indexHamilton County: 44 indexHendricks County: 35 indexHenry County: 37 indexHoward County: 43 indexKnox County: 36 indexLake County: 53 indexLaPorte County: 43 indexMadison County: 41 indexMarion County: 54 indexMonroe County: 36 indexPerry County: 36 indexPorter County: 44 indexPosey County: 35 indexSt. Joseph County: 43 indexShelby County: 35 indexSpencer County: 39 indexTippecanoe County: 39 indexVanderburgh County: 47 indexVigo County: 45 indexWabash County: 34 indexWarrick County: 37 indexWhitley County: 39 index
  • Under 35
  • 35 to 37
  • 37 to 41
  • 41 to 43
  • 43 to 44
  • 44 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Hendricks 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), Hendricks County, 1998 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), Hendricks County, 1998 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/hendricks-county-indiana. 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), Hendricks County, 1998 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/hendricks-county-indiana.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Hendricks County, 1998 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/hendricks-county-indiana (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), Hendricks County, 1998 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/hendricks-county-indiana. 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), Hendricks County, 1998 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/hendricks-county-indiana
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/hendricks-county-indiana.
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 Hendricks County?

Median Air Quality Index (US EPA) in Hendricks County was 35 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: median daily AQI. Retrieved by Invokely on 2026-10-12.

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

64 in 1998, the highest value since 1998 in this series.

Related statistics for Hendricks County

All statistics for Hendricks County | Hendricks County in figures