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

Median Air Quality Index (US EPA) in Oxford County

Median Air Quality Index (US EPA) in Oxford County was 38 in 2025, according to the U.S. Environmental Protection Agency. That is up 6 from 2024.

2025, index38
Change on 2024+6
Series high401982
Series low71981

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 Oxford County, 1981 to 2025

01020304019811991199720032009201520251981: 7 index1982: 40 index1987: 25 index1988: 21 index1989: 24 index1990: 20 index1991: 17 index1992: 23 index1993: 29 index1994: 30 index1995: 31 index1996: 26 index1997: 25 index1998: 27 index1999: 26 index2000: 27 index2001: 30 index2002: 31 index2003: 30 index2004: 30 index2005: 32 index2006: 31 index2007: 31 index2008: 30 index2009: 29 index2010: 34 index2011: 31 index2012: 31 index2013: 30 index2014: 31 index2015: 39 index2016: 35 index2017: 40 index2018: 39 index2019: 33 index2020: 36 index2021: 35 index2022: 33 index2023: 38 index2024: 32 index2025: 38 index01020304019811999201320251981: 7 index1982: 40 index1987: 25 index1988: 21 index1989: 24 index1990: 20 index1991: 17 index1992: 23 index1993: 29 index1994: 30 index1995: 31 index1996: 26 index1997: 25 index1998: 27 index1999: 26 index2000: 27 index2001: 30 index2002: 31 index2003: 30 index2004: 30 index2005: 32 index2006: 31 index2007: 31 index2008: 30 index2009: 29 index2010: 34 index2011: 31 index2012: 31 index2013: 30 index2014: 31 index2015: 39 index2016: 35 index2017: 40 index2018: 39 index2019: 33 index2020: 36 index2021: 35 index2022: 33 index2023: 38 index2024: 32 index2025: 38 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 41 values
Periodindex
202538
202432
202338
202233
202135
202036
201933
201839
201740
201635
201539
201431
201330
201231
201131
201034
200929
200830
200731
200631
200532
200430
200330
200231
200130
200027
199926
199827
199725
199626
199531
199430
199329
199223
199117
199020
198924
198821
198725
198240
19817

Oxford County compared with nearby places

Androscoggin County: 34 indexAroostook County: 32 indexCumberland County: 39 indexHancock County: 35 indexKennebec County: 34 indexKnox County: 33 indexOxford County: 38 indexPenobscot County: 33 indexSagadahoc County: 35 indexWashington County: 34 indexYork County: 34 index
  • Under 33
  • 33 to 34
  • 34 to 35
  • 35 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Oxford 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), Oxford County, 1981 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), Oxford County, 1981 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/oxford-county-maine. 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), Oxford County, 1981 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/oxford-county-maine.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Oxford County, 1981 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/oxford-county-maine (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), Oxford County, 1981 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/oxford-county-maine. 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), Oxford County, 1981 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/oxford-county-maine
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/oxford-county-maine.
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 Oxford County?

Median Air Quality Index (US EPA) in Oxford County was 38 in 2025, according to the U.S. Environmental Protection Agency. That is up 6 from 2024.

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 Oxford County?

40 in 1982, the highest value since 1981 in this series.

Related statistics for Oxford County

All statistics for Oxford County | Oxford County in figures