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

Median Air Quality Index (US EPA) in Northumberland County

Median Air Quality Index (US EPA) in Northumberland County was 12 in 2003, according to the U.S. Environmental Protection Agency. That is up 2 from 2002.

2003, index12
Change on 2002+2
Series high181992
Series low102002

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 Northumberland County, 1992 to 2003

10121416181992199419961998200020031992: 18 index1993: 16 index1994: 16 index1995: 13 index1996: 13 index1997: 12 index1998: 14 index1999: 12 index2000: 13 index2001: 13 index2002: 10 index2003: 12 index101214161819921996200020031992: 18 index1993: 16 index1994: 16 index1995: 13 index1996: 13 index1997: 12 index1998: 14 index1999: 12 index2000: 13 index2001: 13 index2002: 10 index2003: 12 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 12 values
Periodindex
200312
200210
200113
200013
199912
199814
199712
199613
199513
199416
199316
199218

Northumberland County compared with nearby places

Arlington County: 48 indexCaroline County: 43 indexCarroll County: 14 indexCharles City County: 42 indexChesterfield County: 49 indexCulpeper County: 14 indexFairfax County: 57 indexFauquier County: 38 indexFrederick County: 42 indexGiles County: 41 indexHanover County: 44 indexHenrico County: 50 indexKing William County: 12 indexLoudoun County: 43 indexMadison County: 46 indexNorthumberland County: 12 indexPage County: 49 indexPrince Edward County: 36 indexPrince William County: 33 indexRoanoke County: 34 indexRockbridge County: 43 indexRockingham County: 30 indexStafford County: 42 indexWarren County: 14 indexWythe County: 45 indexAlexandria city: 38 indexBristol city: 59 indexCharlottesville city: 15 indexChesapeake city: 54 indexFredericksburg city: 14 indexHampton city: 39 indexLynchburg city: 56 indexNewport News city: 52 indexNorfolk city: 33 indexRichmond city: 57 indexRoanoke city: 23 indexSalem city: 59 indexSuffolk city: 45 indexVirginia Beach city: 54 indexWinchester city: 16 index
  • Under 16
  • 16 to 36
  • 36 to 42
  • 42 to 45
  • 45 to 53
  • 53 and over
  • No data
Median Air Quality Index (US EPA), 2003, index. Northumberland 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), Northumberland County, 1992 to 2003) [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), Northumberland County, 1992 to 2003. 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/northumberland-county-virginia. 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), Northumberland County, 1992 to 2003. 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/northumberland-county-virginia.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Northumberland County, 1992 to 2003 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/median-air-quality-index/northumberland-county-virginia (Accessed: 12 October 2026).

BibTeX
@misc{environmental_median_air_quality_index_2003,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Median Air Quality Index (US EPA), Northumberland County, 1992 to 2003}},
  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/northumberland-county-virginia. 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), Northumberland County, 1992 to 2003
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/northumberland-county-virginia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/northumberland-county-virginia.
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 Northumberland County?

Median Air Quality Index (US EPA) in Northumberland County was 12 in 2003, according to the U.S. Environmental Protection Agency. That is up 2 from 2002.

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 Northumberland County?

18 in 1992, the highest value since 1992 in this series.

Related statistics for Northumberland County

All statistics for Northumberland County | Northumberland County in figures