Data / Median Air Quality Index (US EPA) / Prince William County

Median Air Quality Index (US EPA) in Prince William County

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

2025, index35
Change on 20240
Series high901980
Series low201990

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 Prince William County, 1980 to 2025

2040608010019801995200120072013201920251980: 90 index1990: 20 index1991: 45 index1992: 38 index1993: 48 index1994: 39 index1995: 33 index1996: 34 index1997: 34 index1998: 35 index1999: 37 index2000: 32 index2001: 34 index2002: 34 index2003: 33 index2004: 32 index2005: 31 index2006: 31 index2007: 37 index2008: 31 index2009: 27 index2010: 31 index2011: 29 index2012: 31 index2013: 29 index2014: 30 index2015: 30 index2016: 31 index2017: 34 index2018: 32 index2019: 36 index2020: 32 index2021: 35 index2022: 35 index2023: 37 index2024: 35 index2025: 35 index2040608010019802002201520251980: 90 index1990: 20 index1991: 45 index1992: 38 index1993: 48 index1994: 39 index1995: 33 index1996: 34 index1997: 34 index1998: 35 index1999: 37 index2000: 32 index2001: 34 index2002: 34 index2003: 33 index2004: 32 index2005: 31 index2006: 31 index2007: 37 index2008: 31 index2009: 27 index2010: 31 index2011: 29 index2012: 31 index2013: 29 index2014: 30 index2015: 30 index2016: 31 index2017: 34 index2018: 32 index2019: 36 index2020: 32 index2021: 35 index2022: 35 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 37 values
Periodindex
202535
202435
202337
202235
202135
202032
201936
201832
201734
201631
201530
201430
201329
201231
201129
201031
200927
200831
200737
200631
200531
200432
200333
200234
200134
200032
199937
199835
199734
199634
199533
199439
199348
199238
199145
199020
198090

Prince William County compared with nearby places

Albemarle County: 38 indexArlington County: 37 indexCaroline County: 35 indexCarroll County: 7 indexCharles City County: 35 indexChesterfield County: 39 indexFairfax County: 42 indexFauquier County: 34 indexFrederick County: 39 indexGiles County: 37 indexHanover County: 36 indexHenrico County: 40 indexLoudoun County: 40 indexMadison County: 40 indexPrince Edward County: 33 indexPrince William County: 35 indexRoanoke County: 37 indexRockbridge County: 36 indexRockingham County: 39 indexStafford County: 35 indexWythe County: 39 indexBristol city: 34 indexHampton city: 38 indexHopewell city: 6 indexLynchburg city: 30 indexNorfolk city: 33 indexRichmond city: 36 indexSalem city: 31 indexSuffolk city: 38 indexVirginia Beach city: 34 index
  • Under 33
  • 33 to 35
  • 35 to 36
  • 36 to 38
  • 38 to 39
  • 39 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Prince William 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), Prince William County, 1980 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), Prince William County, 1980 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/prince-william-county-virginia. 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), Prince William County, 1980 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/prince-william-county-virginia.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Prince William County, 1980 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/prince-william-county-virginia (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), Prince William County, 1980 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/prince-william-county-virginia. 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), Prince William County, 1980 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/prince-william-county-virginia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/prince-william-county-virginia.
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 Prince William County?

Median Air Quality Index (US EPA) in Prince William 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 Prince William County?

90 in 1980, the highest value since 1980 in this series.

Related statistics for Prince William County

All statistics for Prince William County | Prince William County in figures