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)

Clearfield County had the highest share of days with good air quality (US EPA AQI) of 40 counties in 2022, at 98.2%. Lancaster County had the lowest, at 23%. The median was 68.5%. Source: EPA.

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Highest98.2Clearfield County
Lowest23Lancaster County
Median68.540 counties

Map of counties, 2022

Adams County: 60.5 %Allegheny County: 35.3 %Armstrong County: 54.2 %Beaver County: 47.8 %Berks County: 65.8 %Blair County: 64.5 %Bradford County: 81.2 %Bucks County: 82.7 %Cambria County: 47.1 %Centre County: 65.8 %Chester County: 68.4 %Clearfield County: 98.2 %Cumberland County: 59.2 %Dauphin County: 54.2 %Delaware County: 52.3 %Elk County: 97.2 %Erie County: 78.4 %Fayette County: 72.2 %Franklin County: 94.9 %Greene County: 78.6 %Indiana County: 72.3 %Lackawanna County: 71.3 %Lancaster County: 23 %Lawrence County: 91.8 %Lebanon County: 61.5 %Lehigh County: 68.5 %Luzerne County: 95.3 %Lycoming County: 72.7 %Mercer County: 78.9 %Monroe County: 91.1 %Montgomery County: 65.5 %Northampton County: 62.6 %Philadelphia County: 42.5 %Somerset County: 97.5 %Susquehanna County: 78.5 %Tioga County: 82.1 %Washington County: 47.4 %Westmoreland County: 65.1 %Wyoming County: 81.1 %York County: 56.2 %
  • Under 53
  • 53 to 63
  • 63 to 68
  • 68 to 79
  • 79 to 87
  • 87 and over
  • No data
%, 2022. 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, 2022

Clearfield County: 98.2 %Clearfield County98.2Somerset County: 97.5 %Somerset County97.5Elk County: 97.2 %Elk County97.2Luzerne County: 95.3 %Luzerne County95.3Franklin County: 94.9 %Franklin County94.9Lawrence County: 91.8 %Lawrence County91.8Monroe County: 91.1 %Monroe County91.1Bucks County: 82.7 %Bucks County82.7Tioga County: 82.1 %Tioga County82.1Bradford County: 81.2 %Bradford County81.2Wyoming County: 81.1 %Wyoming County81.1Mercer County: 78.9 %Mercer County78.9Greene County: 78.6 %Greene County78.6Susquehanna County: 78.5 %Susquehanna County78.5Erie County: 78.4 %Erie County78.4Lycoming County: 72.7 %Lycoming County72.7Indiana County: 72.3 %Indiana County72.3Fayette County: 72.2 %Fayette County72.2Lackawanna County: 71.3 %Lackawanna County71.3Lehigh County: 68.5 %Lehigh County68.5Chester County: 68.4 %Chester County68.4Berks County: 65.8 %Berks County65.8Centre County: 65.8 %Centre County65.8Montgomery County: 65.5 %Montgomery County65.5Westmoreland County: 65.1 %Westmoreland County65.1Blair County: 64.5 %Blair County64.5Northampton County: 62.6 %Northampton County62.6Lebanon County: 61.5 %Lebanon County61.5Adams County: 60.5 %Adams County60.5Cumberland County: 59.2 %Cumberland County59.2York County: 56.2 %York County56.2Armstrong County: 54.2 %Armstrong County54.2Dauphin County: 54.2 %Dauphin County54.2Delaware County: 52.3 %Delaware County52.3Beaver County: 47.8 %Beaver County47.8Washington County: 47.4 %Washington County47.4Cambria County: 47.1 %Cambria County47.1Philadelphia County: 42.5 %Philadelphia County42.5Allegheny County: 35.3 %Allegheny County35.3Lancaster County: 23 %Lancaster County23Clearfield County: 98.2 %Clearfield County98.2Somerset County: 97.5 %Somerset County97.5Elk County: 97.2 %Elk County97.2Luzerne County: 95.3 %Luzerne County95.3Franklin County: 94.9 %Franklin County94.9Lawrence County: 91.8 %Lawrence County91.8Monroe County: 91.1 %Monroe County91.1Bucks County: 82.7 %Bucks County82.7Tioga County: 82.1 %Tioga County82.1Bradford County: 81.2 %Bradford County81.2Wyoming County: 81.1 %Wyoming County81.1Mercer County: 78.9 %Mercer County78.9Greene County: 78.6 %Greene County78.6Susquehanna County: 78.5 %Susquehanna County78.5Erie County: 78.4 %Erie County78.4Lycoming County: 72.7 %Lycoming County72.7Indiana County: 72.3 %Indiana County72.3Fayette County: 72.2 %Fayette County72.2Lackawanna County: 71.3 %Lackawanna County71.3Lehigh County: 68.5 %Lehigh County68.5Chester County: 68.4 %Chester County68.4Berks County: 65.8 %Berks County65.8Centre County: 65.8 %Centre County65.8Montgomery County: 65.5 %Montgomery County65.5Westmoreland County: 65.1 %Westmoreland County65.1Blair County: 64.5 %Blair County64.5Northampton County: 62.6 %Northampton County62.6Lebanon County: 61.5 %Lebanon County61.5Adams County: 60.5 %Adams County60.5Cumberland County: 59.2 %Cumberland County59.2York County: 56.2 %York County56.2Armstrong County: 54.2 %Armstrong County54.2Dauphin County: 54.2 %Dauphin County54.2Delaware County: 52.3 %Delaware County52.3Beaver County: 47.8 %Beaver County47.8Washington County: 47.4 %Washington County47.4Cambria County: 47.1 %Cambria County47.1Philadelphia County: 42.5 %Philadelphia County42.5Allegheny County: 35.3 %Allegheny County35.3Lancaster County: 23 %Lancaster County23
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2022 (%)Change on 2021
1Clearfield County98.2-0.7 pts
2Somerset County97.5+4.1 pts
3Elk County97.2+2.2 pts
4Luzerne County95.3+1.2 pts
5Franklin County94.9-0.2 pts
6Lawrence County91.8-1.4 pts
7Monroe County91.1-0.7 pts
8Bucks County82.7-1.8 pts
9Tioga County82.1+3.8 pts
10Bradford County81.2+13.2 pts
11Wyoming County81.1+5.5 pts
12Mercer County78.9+2.6 pts
13Greene County78.6+10.4 pts
14Susquehanna County78.5+3.1 pts
15Erie County78.4+0.9 pts
16Lycoming County72.7+10.3 pts
17Indiana County72.3+9.7 pts
18Fayette County72.2+8.1 pts
19Lackawanna County71.3-0.1 pts
20Lehigh County68.5+12.4 pts
21Chester County68.4+6.4 pts
22Berks County65.8+11.6 pts
22Centre County65.8-0.2 pts
24Montgomery County65.5+8.8 pts
25Westmoreland County65.1+9.7 pts
26Blair County64.5+3.2 pts
27Northampton County62.6+4 pts
28Lebanon County61.5+7.5 pts
29Adams County60.5+3.9 pts
30Cumberland County59.2+1.9 pts
31York County56.2+9.1 pts
32Armstrong County54.2+1.6 pts
32Dauphin County54.2+11 pts
34Delaware County52.3+2.4 pts
35Beaver County47.8+1.2 pts
36Washington County47.4-3.8 pts
37Cambria County47.1-0.8 pts
38Philadelphia County42.5+5 pts
39Allegheny County35.3+3 pts
40Lancaster County23-4.4 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. 4 counties with data in other periods have no value for 2022 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), 2022) [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), 2022. 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=2022. 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), 2022. 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=2022.

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), 2022 [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=2022 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_pennsylvania_by_2022,
  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), 2022}},
  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=2022. 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), 2022
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=2022
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/pennsylvania-counties?period=2022.
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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Rank Counties in Pennsylvania by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

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

Clearfield County, with 98.2% in 2022, according to EPA.

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

Lancaster County, with 23% in 2022.

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. 4 counties have no value for 2022 and are not ranked.

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

Counties in Pennsylvania: more rankings