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

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

Highest daily Air Quality Index (US EPA) in Northumberland County was 65 in 2003, according to the U.S. Environmental Protection Agency. That is up 14 from 2002.

2003, index65
Change on 2002+14
Series high652003
Series low412000

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

Get an email when a new figure is out or this one is revised.
Keep it in a collection in your library.

Highest daily Air Quality Index (US EPA) in Northumberland County, 1992 to 2003

4045505560651992199419961998200020031992: 54 index1993: 51 index1994: 44 index1995: 42 index1996: 46 index1997: 52 index1998: 47 index1999: 49 index2000: 41 index2001: 44 index2002: 51 index2003: 65 index4050607019921996200020031992: 54 index1993: 51 index1994: 44 index1995: 42 index1996: 46 index1997: 52 index1998: 47 index1999: 49 index2000: 41 index2001: 44 index2002: 51 index2003: 65 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 12 values
Periodindex
200365
200251
200144
200041
199949
199847
199752
199646
199542
199444
199351
199254

Northumberland County compared with nearby places

Arlington County: 210 indexCaroline County: 202 indexCarroll County: 44 indexCharles City County: 185 indexChesterfield County: 197 indexCulpeper County: 46 indexFairfax County: 219 indexFauquier County: 179 indexFrederick County: 172 indexGiles County: 169 indexHanover County: 185 indexHenrico County: 187 indexKing William County: 55 indexLoudoun County: 212 indexMadison County: 200 indexNorthumberland County: 65 indexPage County: 197 indexPrince Edward County: 133 indexPrince William County: 204 indexRoanoke County: 164 indexRockbridge County: 143 indexRockingham County: 72 indexStafford County: 204 indexWarren County: 44 indexWythe County: 174 indexAlexandria city: 202 indexBristol city: 147 indexCharlottesville city: 41 indexChesapeake city: 154 indexFredericksburg city: 51 indexHampton city: 207 indexLynchburg city: 111 indexNewport News city: 152 indexNorfolk city: 154 indexRichmond city: 123 indexRoanoke city: 117 indexSalem city: 115 indexSuffolk city: 205 indexVirginia Beach city: 156 indexWinchester city: 50 index
  • Under 60
  • 60 to 130
  • 130 to 160
  • 160 to 190
  • 190 to 200
  • 200 and over
  • No data
Highest daily 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

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.

Report a problem with this figure

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), 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: highest daily AQI, Highest daily 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/highest-daily-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: highest daily AQI. Highest daily 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/highest-daily-air-quality-index/northumberland-county-virginia.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily 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/highest-daily-air-quality-index/northumberland-county-virginia (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2003,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily 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/highest-daily-air-quality-index/northumberland-county-virginia. 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), 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/highest-daily-air-quality-index/northumberland-county-virginia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/northumberland-county-virginia.
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  -
Embed this chart

Paste this code into a web page or a blog post. The chart shows the latest figures as they are published, with the source and a link back to this page.

Sites that read oEmbed links, such as WordPress, can show the chart when you paste the link to this page.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

What is the latest highest daily Air Quality Index (US EPA) in Northumberland County? Cite the source.
get_value {"indicator":"aqi_max","place":"us-county-51133"}
GET https://invokely.ai/api/v1/value?indicator=aqi_max&place=us-county-51133

Connect Claude, ChatGPT or Cursor in one step. The trial answers 25 calls a day without an account.

Questions

What is the highest daily Air Quality Index (US EPA) in Northumberland County?

Highest daily Air Quality Index (US EPA) in Northumberland County was 65 in 2003, according to the U.S. Environmental Protection Agency. That is up 14 from 2002.

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 Northumberland County?

65 in 2003, the highest value since 1992 in this series.

Related statistics for Northumberland County

All statistics for Northumberland County | Northumberland County in figures