Data / Share of days with good air quality (US EPA AQI) / King William County

Share of days with good air quality (US EPA AQI) in King William County

Share of days with good air quality (US EPA AQI) in King William County was 100% in 2016, according to EPA. That is unchanged from 2015.

2016100%
Change on 20150 pts
Series high1001992
Series low93.31991

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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Share of days with good air quality (US EPA AQI) in King William County, 1990 to 2016

9294969810019901994199820022006201020161990: 98.3 %1991: 93.3 %1992: 100 %1993: 100 %1994: 100 %1995: 100 %1996: 96.7 %1997: 98.4 %1998: 100 %1999: 100 %2000: 100 %2001: 100 %2002: 100 %2003: 98.3 %2004: 100 %2005: 100 %2006: 100 %2007: 100 %2008: 100 %2009: 100 %2010: 100 %2011: 98.2 %2012: 100 %2013: 100 %2014: 100 %2015: 100 %2016: 100 %9294969810019901999200820161990: 98.3 %1991: 93.3 %1992: 100 %1993: 100 %1994: 100 %1995: 100 %1996: 96.7 %1997: 98.4 %1998: 100 %1999: 100 %2000: 100 %2001: 100 %2002: 100 %2003: 98.3 %2004: 100 %2005: 100 %2006: 100 %2007: 100 %2008: 100 %2009: 100 %2010: 100 %2011: 98.2 %2012: 100 %2013: 100 %2014: 100 %2015: 100 %2016: 100 %
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12, published 2026-07-13.
All 27 values
Period%
2016100
2015100
2014100
2013100
2012100
201198.2
2010100
2009100
2008100
2007100
2006100
2005100
2004100
200398.3
2002100
2001100
2000100
1999100
1998100
199798.4
199696.7
1995100
1994100
1993100
1992100
199193.3
199098.3

King William County compared with nearby places

Albemarle County: 77.3 %Arlington County: 77.9 %Caroline County: 87.9 %Carroll County: 100 %Charles City County: 90.5 %Chesterfield County: 80 %Fairfax County: 62.3 %Fauquier County: 92.5 %Frederick County: 71.5 %Giles County: 91.5 %Hanover County: 84.1 %Henrico County: 68.4 %King William County: 100 %Loudoun County: 82.5 %Madison County: 83.7 %Prince Edward County: 96 %Prince William County: 88.3 %Roanoke County: 75.4 %Rockbridge County: 90.5 %Rockingham County: 87.4 %Stafford County: 83.9 %Wythe County: 91.8 %Alexandria city: 96.7 %Bristol city: 69.7 %Fredericksburg city: 100 %Hampton city: 84 %Hopewell city: 100 %Lynchburg city: 80 %Norfolk city: 95 %Richmond city: 62.5 %Salem city: 67.5 %Suffolk city: 90.7 %Virginia Beach city: 80.1 %Winchester city: 100 %
  • Under 73
  • 73 to 80
  • 80 to 86
  • 86 to 91
  • 91 to 96
  • 96 and over
  • No data
Share of days with good air quality (US EPA AQI), 2016, %. King William 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

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

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: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts (Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016) [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: good days as a share of days with an AQI, calculated with stored counts, Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/good-air-quality-days-share/king-william-county-virginia. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/good-air-quality-days-share/king-william-county-virginia.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/king-william-county-virginia (Accessed: 12 October 2026).

BibTeX
@misc{environmental_share_of_days_with_2016,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016}},
  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/good-air-quality-days-share/king-william-county-virginia. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. 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: good days as a share of days with an AQI, calculated with stored counts: Share of days with good air quality (US EPA AQI), King William County, 1990 to 2016
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/good-air-quality-days-share/king-william-county-virginia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/king-william-county-virginia.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Questions

What is the share of days with good air quality (US EPA AQI) in King William County?

Share of days with good air quality (US EPA AQI) in King William County was 100% in 2016, according to EPA. That is unchanged from 2015.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved by Invokely on 2026-10-12.

What was the highest share of days with good air quality (US EPA AQI) in King William County?

100% in 1992, the highest value since 1990 in this series.

Related statistics for King William County

All statistics for King William County | King William County in figures