Data / Highest daily Air Quality Index (US EPA) / Franklin County

Highest daily Air Quality Index (US EPA) in Franklin County

Highest daily Air Quality Index (US EPA) in Franklin County was 75 in 2017, according to the U.S. Environmental Protection Agency. That is up 3 from 2016.

2017, index75
Change on 2016+3
Series high1541987
Series low61982

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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Highest daily Air Quality Index (US EPA) in Franklin County, 1981 to 2017

05010015020019811987199119951999200320171981: 10 index1982: 6 index1985: 55 index1986: 122 index1987: 154 index1988: 60 index1989: 57 index1990: 48 index1991: 52 index1992: 57 index1993: 40 index1994: 42 index1995: 52 index1996: 43 index1997: 31 index1998: 53 index1999: 44 index2000: 28 index2001: 40 index2002: 36 index2003: 44 index2004: 31 index2015: 51 index2016: 72 index2017: 75 index0501001502001981199220171981: 10 index1982: 6 index1985: 55 index1986: 122 index1987: 154 index1988: 60 index1989: 57 index1990: 48 index1991: 52 index1992: 57 index1993: 40 index1994: 42 index1995: 52 index1996: 43 index1997: 31 index1998: 53 index1999: 44 index2000: 28 index2001: 40 index2002: 36 index2003: 44 index2004: 31 index2015: 51 index2016: 72 index2017: 75 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 25 values
Periodindex
201775
201672
201551
200431
200344
200236
200140
200028
199944
199853
199731
199643
199552
199442
199340
199257
199152
199048
198957
198860
1987154
1986122
198555
19826
198110

Franklin County compared with nearby places

Androscoggin County: 100 indexAroostook County: 120 indexCumberland County: 150 indexFranklin County: 75 indexHancock County: 182 indexKennebec County: 100 indexKnox County: 143 indexOxford County: 87 indexPenobscot County: 80 indexWashington County: 147 indexYork County: 159 index
  • Under 87
  • 87 to 100
  • 100 to 140
  • 140 to 150
  • 150 and over
  • No data
Highest daily Air Quality Index (US EPA), 2017, index. Franklin 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

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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: highest 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: highest daily AQI (Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017) [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: highest daily AQI, Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/highest-daily-air-quality-index/franklin-county-maine. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/highest-daily-air-quality-index/franklin-county-maine.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/franklin-county-maine (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2017,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017}},
  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/highest-daily-air-quality-index/franklin-county-maine. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Highest daily Air Quality Index (US EPA), Franklin County, 1981 to 2017
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/highest-daily-air-quality-index/franklin-county-maine
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/franklin-county-maine.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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 highest daily Air Quality Index (US EPA) in Franklin County?

Highest daily Air Quality Index (US EPA) in Franklin County was 75 in 2017, according to the U.S. Environmental Protection Agency. That is up 3 from 2016.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: highest daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest highest daily Air Quality Index (US EPA) in Franklin County?

154 in 1987, the highest value since 1981 in this series.

Related statistics for Franklin County

All statistics for Franklin County | Franklin County in figures