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

Median Air Quality Index (US EPA) in Philadelphia County

Median Air Quality Index (US EPA) in Philadelphia County was 50 in 2025, according to the U.S. Environmental Protection Agency. That is down 2 from 2024. That is the 2nd highest of 38 counties in 2025.

2025, index50
Change on 2024-2
Rank2nd of 38Counties in Pennsylvania ranked
Series high681980
Series low472020

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 Philadelphia County, 1980 to 2025

45505560657019801987199420012008201520251980: 68 index1981: 68 index1982: 68 index1983: 68 index1984: 68 index1985: 57 index1986: 61 index1987: 68 index1988: 57 index1989: 57 index1990: 51 index1991: 57 index1992: 48 index1993: 57 index1994: 57 index1995: 57 index1996: 57 index1997: 52 index1998: 55 index1999: 59 index2000: 61 index2001: 67 index2002: 61 index2003: 60 index2004: 60 index2005: 60 index2006: 61 index2007: 61 index2008: 60 index2009: 56 index2010: 57 index2011: 58 index2012: 60 index2013: 58 index2014: 59 index2015: 56 index2016: 55 index2017: 56 index2018: 54 index2019: 49 index2020: 47 index2021: 54 index2022: 52 index2023: 58 index2024: 52 index2025: 50 index4050607019801996201220251980: 68 index1981: 68 index1982: 68 index1983: 68 index1984: 68 index1985: 57 index1986: 61 index1987: 68 index1988: 57 index1989: 57 index1990: 51 index1991: 57 index1992: 48 index1993: 57 index1994: 57 index1995: 57 index1996: 57 index1997: 52 index1998: 55 index1999: 59 index2000: 61 index2001: 67 index2002: 61 index2003: 60 index2004: 60 index2005: 60 index2006: 61 index2007: 61 index2008: 60 index2009: 56 index2010: 57 index2011: 58 index2012: 60 index2013: 58 index2014: 59 index2015: 56 index2016: 55 index2017: 56 index2018: 54 index2019: 49 index2020: 47 index2021: 54 index2022: 52 index2023: 58 index2024: 52 index2025: 50 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 46 values
Periodindex
202550
202452
202358
202252
202154
202047
201949
201854
201756
201655
201556
201459
201358
201260
201158
201057
200956
200860
200761
200661
200560
200460
200360
200261
200167
200061
199959
199855
199752
199657
199557
199457
199357
199248
199157
199051
198957
198857
198768
198661
198557
198468
198368
198268
198168
198068

Philadelphia County compared with nearby places

Adams County: 42 indexAllegheny County: 52 indexArmstrong County: 41 indexBeaver County: 46 indexBerks County: 43 indexBlair County: 40 indexBradford County: 37 indexBucks County: 36 indexCambria County: 41 indexCentre County: 41 indexChester County: 43 indexCumberland County: 35 indexDauphin County: 44 indexDelaware County: 44 indexElk County: 36 indexErie County: 34 indexFayette County: 40 indexFranklin County: 37 indexGreene County: 40 indexIndiana County: 39 indexLackawanna County: 39 indexLancaster County: 45 indexLebanon County: 42 indexLehigh County: 41 indexLycoming County: 40 indexMercer County: 42 indexMonroe County: 36 indexMontgomery County: 41 indexNorthampton County: 38 indexPhiladelphia County: 50 indexSomerset County: 36 indexSusquehanna County: 22 indexTioga County: 39 indexWarren County: 35 indexWashington County: 44 indexWestmoreland County: 39 indexWyoming County: 24 indexYork County: 45 index
  • Under 36
  • 36 to 39
  • 39 to 40
  • 40 to 42
  • 42 to 44
  • 44 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Philadelphia 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), Philadelphia 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), Philadelphia 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/philadelphia-county-pennsylvania. 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), Philadelphia 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/philadelphia-county-pennsylvania.

Harvard

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

Median Air Quality Index (US EPA) in Philadelphia County was 50 in 2025, according to the U.S. Environmental Protection Agency. That is down 2 from 2024. That is the 2nd highest of 38 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 Philadelphia County?

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

Related statistics for Philadelphia County

All statistics for Philadelphia County | Philadelphia County in figures