Data / Share of days with good air quality (US EPA AQI) / Falls Church city

Share of days with good air quality (US EPA AQI) in Falls Church city

Share of days with good air quality (US EPA AQI) in Falls Church city was 40% in 1989, according to EPA. That is down 46 pts from 1988.

198940%
Change on 1988-46 pts
Series high1001987
Series low401989

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.

Share of days with good air quality (US EPA AQI) in Falls Church city, 1987 to 1989

4060801001987198819891987: 100 %1988: 86 %1989: 40 %4060801001987198819891987: 100 %1988: 86 %1989: 40 %
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12, published 2026-07-13.
All 3 values
Period%
198940
198886
1987100

Falls Church city compared with nearby places

Arlington County: 64.4 %Augusta County: 84.9 %Buchanan County: 88.9 %Campbell County: 100 %Carroll County: 93.8 %Charles City County: 81 %Chesterfield County: 59.7 %Fairfax County: 43.8 %Fauquier County: 58.9 %Hanover County: 52.8 %Henrico County: 79.4 %Madison County: 70.3 %Northampton County: 56.5 %Roanoke County: 75.1 %Smyth County: 64.3 %Warren County: 72.9 %York County: 100 %Alexandria city: 64.9 %Bristol city: 91.9 %Charlottesville city: 93.4 %Chesapeake city: 93.3 %Covington city: 90 %Fairfax city: 70.1 %Falls Church city: 40 %Fredericksburg city: 100 %Hampton city: 78.7 %Hopewell city: 96.6 %Lynchburg city: 98.3 %Martinsville city: 98.2 %Newport News city: 100 %Norfolk city: 85.8 %Portsmouth city: 100 %Richmond city: 77 %Roanoke city: 85.5 %Suffolk city: 76.3 %Virginia Beach city: 90.9 %Winchester city: 94.7 %
  • Under 64
  • 64 to 75
  • 75 to 85
  • 85 to 92
  • 92 to 98
  • 98 and over
  • No data
Share of days with good air quality (US EPA AQI), 1989, %. Falls Church city 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.

Report a problem with this figure

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), Falls Church city, 1987 to 1989) [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), Falls Church city, 1987 to 1989. 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/falls-church-city-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), Falls Church city, 1987 to 1989. 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/falls-church-city-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), Falls Church city, 1987 to 1989 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/falls-church-city-virginia (Accessed: 12 October 2026).

BibTeX
@misc{environmental_share_of_days_with_1989,
  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), Falls Church city, 1987 to 1989}},
  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/falls-church-city-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), Falls Church city, 1987 to 1989
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/falls-church-city-virginia
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/falls-church-city-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  -
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 share of days with good air quality (US EPA AQI) in Falls Church city? Cite the source.
get_value {"indicator":"aqi_good_days_share","place":"us-county-51610"}
GET https://invokely.ai/api/v1/value?indicator=aqi_good_days_share&place=us-county-51610

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

Questions

What is the share of days with good air quality (US EPA AQI) in Falls Church city?

Share of days with good air quality (US EPA AQI) in Falls Church city was 40% in 1989, according to EPA. That is down 46 pts from 1988.

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 Falls Church city?

100% in 1987, the highest value since 1987 in this series.

Related statistics for Falls Church city

All statistics for Falls Church city | Falls Church city in figures