Median Air Quality Index (US EPA) in Durham County

Median Air Quality Index (US EPA) in Durham County was 42 in 2025, according to the U.S. Environmental Protection Agency. That is down 9 from 2024.

2025, index42
Change on 2024-9
Series high632000
Series low231992

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 Durham County, 1980 to 2025

20304050607019801987199420012008201520251980: 49 index1981: 47 index1982: 42 index1983: 39 index1984: 50 index1985: 36 index1986: 42 index1987: 40 index1988: 40 index1989: 33 index1990: 33 index1991: 30 index1992: 23 index1993: 36 index1994: 40 index1995: 36 index1996: 40 index1997: 41 index1998: 38 index1999: 59 index2000: 63 index2001: 61 index2002: 58 index2003: 57 index2004: 58 index2005: 58 index2006: 58 index2007: 55 index2008: 56 index2009: 52 index2010: 53 index2011: 51 index2012: 47 index2013: 43 index2014: 46 index2015: 48 index2016: 49 index2017: 49 index2018: 48 index2019: 47 index2020: 40 index2021: 44 index2022: 42 index2023: 44 index2024: 51 index2025: 42 index20304050607019801996201220251980: 49 index1981: 47 index1982: 42 index1983: 39 index1984: 50 index1985: 36 index1986: 42 index1987: 40 index1988: 40 index1989: 33 index1990: 33 index1991: 30 index1992: 23 index1993: 36 index1994: 40 index1995: 36 index1996: 40 index1997: 41 index1998: 38 index1999: 59 index2000: 63 index2001: 61 index2002: 58 index2003: 57 index2004: 58 index2005: 58 index2006: 58 index2007: 55 index2008: 56 index2009: 52 index2010: 53 index2011: 51 index2012: 47 index2013: 43 index2014: 46 index2015: 48 index2016: 49 index2017: 49 index2018: 48 index2019: 47 index2020: 40 index2021: 44 index2022: 42 index2023: 44 index2024: 51 index2025: 42 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 46 values
Periodindex
202542
202451
202344
202242
202144
202040
201947
201848
201749
201649
201548
201446
201343
201247
201151
201053
200952
200856
200755
200658
200558
200458
200357
200258
200161
200063
199959
199838
199741
199640
199536
199440
199336
199223
199130
199033
198933
198840
198740
198642
198536
198450
198339
198242
198147
198049

Durham County compared with nearby places

Alexander County: 38 indexAvery County: 38 indexBuncombe County: 40 indexCaldwell County: 36 indexCarteret County: 35 indexCaswell County: 37 indexCatawba County: 42 indexCumberland County: 44 indexDavidson County: 51 indexDurham County: 42 indexEdgecombe County: 38 indexForsyth County: 45 indexGraham County: 41 indexGranville County: 39 indexGuilford County: 41 indexHaywood County: 43 indexHyde County: 24 indexJohnston County: 41 indexLenoir County: 35 indexLincoln County: 41 indexMacon County: 32 indexMartin County: 31 indexMecklenburg County: 51 indexMitchell County: 31 indexMontgomery County: 39 indexNew Hanover County: 41 indexNorthampton County: 33 indexPerson County: 36 indexPitt County: 37 indexRockingham County: 38 indexRowan County: 43 indexSwain County: 37 indexUnion County: 40 indexWake County: 43 index
  • Under 35
  • 35 to 37
  • 37 to 39
  • 39 to 41
  • 41 to 43
  • 43 and over
  • No data
Median Air Quality Index (US EPA), 2025, index. Durham 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), Durham County, 1980 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), Durham County, 1980 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/durham-county-north-carolina. 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), Durham County, 1980 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/durham-county-north-carolina.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Durham County, 1980 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/durham-county-north-carolina (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), Durham County, 1980 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/durham-county-north-carolina. 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), Durham County, 1980 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/durham-county-north-carolina
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/durham-county-north-carolina.
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 Durham County?

Median Air Quality Index (US EPA) in Durham County was 42 in 2025, according to the U.S. Environmental Protection Agency. That is down 9 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 Durham County?

63 in 2000, the highest value since 1980 in this series.

Related statistics for Durham County

All statistics for Durham County | Durham County in figures