Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in Pennsylvania

Counties in Pennsylvania by share of days with good air quality (US EPA AQI)

Franklin County had the highest share of days with good air quality (US EPA AQI) of 37 counties in 2016, at 96.4%. Lebanon County had the lowest, at 26%. The median was 62.8%. Source: EPA.

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Highest96.4Franklin County
Lowest26Lebanon County
Median62.837 counties

Map of counties, 2016

Adams County: 65.3 %Allegheny County: 28.1 %Armstrong County: 43 %Beaver County: 46.4 %Berks County: 37.2 %Blair County: 62.8 %Bradford County: 66.5 %Bucks County: 86 %Cambria County: 57.7 %Centre County: 63.4 %Chester County: 43.3 %Clearfield County: 90.2 %Cumberland County: 47.9 %Dauphin County: 51.4 %Delaware County: 33.1 %Elk County: 92.8 %Erie County: 63.7 %Franklin County: 96.4 %Greene County: 83.7 %Indiana County: 87.3 %Lackawanna County: 64.5 %Lancaster County: 32 %Lawrence County: 91.8 %Lebanon County: 26 %Lehigh County: 42.6 %Luzerne County: 91.8 %Lycoming County: 91.5 %Mercer County: 55.5 %Monroe County: 72.4 %Montgomery County: 83.9 %Northampton County: 41.8 %Philadelphia County: 30.3 %Somerset County: 90.8 %Tioga County: 76.5 %Washington County: 27.6 %Westmoreland County: 40.4 %York County: 48.1 %
  • Under 37
  • 37 to 46
  • 46 to 63
  • 63 to 72
  • 72 to 90
  • 90 and over
  • No data
%, 2016. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2016

Franklin County: 96.4 %Franklin County96.4Elk County: 92.8 %Elk County92.8Lawrence County: 91.8 %Lawrence County91.8Luzerne County: 91.8 %Luzerne County91.8Lycoming County: 91.5 %Lycoming County91.5Somerset County: 90.8 %Somerset County90.8Clearfield County: 90.2 %Clearfield County90.2Indiana County: 87.3 %Indiana County87.3Bucks County: 86 %Bucks County86Montgomery County: 83.9 %Montgomery County83.9Greene County: 83.7 %Greene County83.7Tioga County: 76.5 %Tioga County76.5Monroe County: 72.4 %Monroe County72.4Bradford County: 66.5 %Bradford County66.5Adams County: 65.3 %Adams County65.3Lackawanna County: 64.5 %Lackawanna County64.5Erie County: 63.7 %Erie County63.7Centre County: 63.4 %Centre County63.4Blair County: 62.8 %Blair County62.8Cambria County: 57.7 %Cambria County57.7Mercer County: 55.5 %Mercer County55.5Dauphin County: 51.4 %Dauphin County51.4York County: 48.1 %York County48.1Cumberland County: 47.9 %Cumberland County47.9Beaver County: 46.4 %Beaver County46.4Chester County: 43.3 %Chester County43.3Armstrong County: 43 %Armstrong County43Lehigh County: 42.6 %Lehigh County42.6Northampton County: 41.8 %Northampton County41.8Westmoreland County: 40.4 %Westmoreland County40.4Berks County: 37.2 %Berks County37.2Delaware County: 33.1 %Delaware County33.1Lancaster County: 32 %Lancaster County32Philadelphia County: 30.3 %Philadelphia County30.3Allegheny County: 28.1 %Allegheny County28.1Washington County: 27.6 %Washington County27.6Lebanon County: 26 %Lebanon County26Franklin County: 96.4 %Franklin County96.4Elk County: 92.8 %Elk County92.8Lawrence County: 91.8 %Lawrence County91.8Luzerne County: 91.8 %Luzerne County91.8Lycoming County: 91.5 %Lycoming County91.5Somerset County: 90.8 %Somerset County90.8Clearfield County: 90.2 %Clearfield County90.2Indiana County: 87.3 %Indiana County87.3Bucks County: 86 %Bucks County86Montgomery County: 83.9 %Montgomery County83.9Greene County: 83.7 %Greene County83.7Tioga County: 76.5 %Tioga County76.5Monroe County: 72.4 %Monroe County72.4Bradford County: 66.5 %Bradford County66.5Adams County: 65.3 %Adams County65.3Lackawanna County: 64.5 %Lackawanna County64.5Erie County: 63.7 %Erie County63.7Centre County: 63.4 %Centre County63.4Blair County: 62.8 %Blair County62.8Cambria County: 57.7 %Cambria County57.7Mercer County: 55.5 %Mercer County55.5Dauphin County: 51.4 %Dauphin County51.4York County: 48.1 %York County48.1Cumberland County: 47.9 %Cumberland County47.9Beaver County: 46.4 %Beaver County46.4Chester County: 43.3 %Chester County43.3Armstrong County: 43 %Armstrong County43Lehigh County: 42.6 %Lehigh County42.6Northampton County: 41.8 %Northampton County41.8Westmoreland County: 40.4 %Westmoreland County40.4Berks County: 37.2 %Berks County37.2Delaware County: 33.1 %Delaware County33.1Lancaster County: 32 %Lancaster County32Philadelphia County: 30.3 %Philadelphia County30.3Allegheny County: 28.1 %Allegheny County28.1Washington County: 27.6 %Washington County27.6Lebanon County: 26 %Lebanon County26
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2016 (%)Change on 2015
1Franklin County96.4+1.7 pts
2Elk County92.8-0.6 pts
3Lawrence County91.8+0.8 pts
3Luzerne County91.8+1.7 pts
5Lycoming County91.5-2.2 pts
6Somerset County90.8-4 pts
7Clearfield County90.2+3.3 pts
8Indiana County87.3+4.7 pts
9Bucks County86+43.2 pts
10Montgomery County83.9+27.5 pts
11Greene County83.7+0.6 pts
12Tioga County76.5+15.1 pts
13Monroe County72.4+5.6 pts
14Bradford County66.5-29.9 pts
15Adams County65.3+17.1 pts
16Lackawanna County64.5+16.3 pts
17Erie County63.7+3.2 pts
18Centre County63.4+7.5 pts
19Blair County62.8+16.8 pts
20Cambria County57.7+22.1 pts
21Mercer County55.5+11.9 pts
22Dauphin County51.4+18.5 pts
23York County48.1+11.1 pts
24Cumberland County47.9+11.3 pts
25Beaver County46.4-1.3 pts
26Chester County43.3+6.9 pts
27Armstrong County43+4.3 pts
28Lehigh County42.6-44.8 pts
29Northampton County41.8+7.8 pts
30Westmoreland County40.4-5.6 pts
31Berks County37.2-3.3 pts
32Delaware County33.1+0.2 pts
33Lancaster County32-1.2 pts
34Philadelphia County30.3+2.1 pts
35Allegheny County28.1-0.7 pts
36Washington County27.6+0.2 pts
37Lebanon County26-21.7 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 7 counties with data in other periods have no value for 2016 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts (Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016) [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: good days as a share of days with an AQI, calculated with stored counts, Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_pennsylvania_by_2016,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016}},
  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/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts: Counties in Pennsylvania by share of days with good air quality (US EPA AQI), 2016
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/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/pennsylvania-counties?period=2016.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Franklin County, with 96.4% in 2016, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Lebanon County, with 26% in 2016.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 7 counties have no value for 2016 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in Pennsylvania: more rankings