Data / Rankings / Median Air Quality Index (US EPA) / Counties in Maine

Counties in Maine by median Air Quality Index (US EPA), 2000

Sagadahoc County had the highest median Air Quality Index (US EPA) of 13 counties in 2000, at 39. Franklin County had the lowest, at 9. The median was 32. Source: the U.S. Environmental Protection Agency.

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Highest39Sagadahoc County
Lowest9Franklin County
Median3213 counties

Map of counties, 2000

Androscoggin County: 14 indexAroostook County: 33 indexCumberland County: 36 indexFranklin County: 9 indexHancock County: 36 indexKennebec County: 32 indexKnox County: 33 indexOxford County: 27 indexPenobscot County: 34 indexPiscataquis County: 32 indexSagadahoc County: 39 indexWashington County: 23 indexYork County: 32 index
  • Under 25
  • 25 to 32
  • 32 to 33
  • 33 to 35
  • 35 and over
  • No data
index, 2000. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2000

Sagadahoc County: 39 indexSagadahoc County39Cumberland County: 36 indexCumberland County36Hancock County: 36 indexHancock County36Penobscot County: 34 indexPenobscot County34Aroostook County: 33 indexAroostook County33Knox County: 33 indexKnox County33Kennebec County: 32 indexKennebec County32Piscataquis County: 32 indexPiscataquis County32York County: 32 indexYork County32Oxford County: 27 indexOxford County27Washington County: 23 indexWashington County23Androscoggin County: 14 indexAndroscoggin County14Franklin County: 9 indexFranklin County9Sagadahoc County: 39 indexSagadahoc County39Cumberland County: 36 indexCumberland County36Hancock County: 36 indexHancock County36Penobscot County: 34 indexPenobscot County34Aroostook County: 33 indexAroostook County33Knox County: 33 indexKnox County33Kennebec County: 32 indexKennebec County32Piscataquis County: 32 indexPiscataquis County32York County: 32 indexYork County32Oxford County: 27 indexOxford County27Washington County: 23 indexWashington County23Androscoggin County: 14 indexAndroscoggin County14Franklin County: 9 indexFranklin County9
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2000
index		Change on 1999
1Sagadahoc County39-4
2Cumberland County360
2Hancock County36-6
4Penobscot County34-2
5Aroostook County33-1
5Knox County33-2
7Kennebec County32-3
7Piscataquis County32-3
7York County32-2
10Oxford County27+1
11Washington County23-6
12Androscoggin County14-1
13Franklin County9-3

Other periods

About this ranking

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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 3 counties with data in other periods have no value for 2000 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: 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 (Counties in Maine by median Air Quality Index (US EPA), 2000) [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, Counties in Maine by median Air Quality Index (US EPA), 2000. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/maine-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Maine by median Air Quality Index (US EPA), 2000. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/maine-counties.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Maine by median Air Quality Index (US EPA), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/maine-counties (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_maine_by_2000,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Maine by median Air Quality Index (US EPA), 2000}},
  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/median-air-quality-index/maine-counties. 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: Counties in Maine by median Air Quality Index (US EPA), 2000
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/median-air-quality-index/maine-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/maine-counties.
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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Rank Counties in Maine by median Air Quality Index (US EPA) using official data, and cite the source.
rank_places {"indicator":"aqi_median","level":"province","within":"Maine","limit":10}
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Questions

Which county has the highest median Air Quality Index (US EPA)?

Sagadahoc County, with 39 in 2000, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Franklin County, with 9 in 2000.

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: median daily AQI. Retrieved 2026-10-12. 3 counties have no value for 2000 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Maine: more rankings