Share of days with good air quality (US EPA AQI) in Walker County
Share of days with good air quality (US EPA AQI) in Walker County was 40.2% in 2011, according to EPA. That is up 9.2 pts from 2010.
Share of days with good air quality (US EPA AQI) in Walker County, 1990 to 2011
All 21 values
| Period | % |
|---|---|
| 2011 | 40.2 |
| 2010 | 31 |
| 2009 | 48.3 |
| 2008 | 35 |
| 2007 | 23.1 |
| 2006 | 22 |
| 2005 | 26.7 |
| 2004 | 30.8 |
| 2003 | 23.1 |
| 2002 | 69.5 |
| 2000 | 21.7 |
| 1999 | 26.2 |
| 1998 | 100 |
| 1997 | 100 |
| 1996 | 98.1 |
| 1995 | 98.2 |
| 1994 | 100 |
| 1993 | 92.9 |
| 1992 | 100 |
| 1991 | 92.7 |
| 1990 | 88.1 |
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.
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
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), Walker County, 1990 to 2011) [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), Walker County, 1990 to 2011. 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/walker-county-alabama. 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), Walker County, 1990 to 2011. 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/walker-county-alabama.
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), Walker County, 1990 to 2011 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/walker-county-alabama (Accessed: 12 October 2026).
BibTeX
@misc{environmental_share_of_days_with_2011,
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), Walker County, 1990 to 2011}},
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/walker-county-alabama. 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), Walker County, 1990 to 2011
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/walker-county-alabama
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/walker-county-alabama.
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 -
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 Walker County? Cite the source.
get_value {"indicator":"aqi_good_days_share","place":"us-county-01127"}
GET https://invokely.ai/api/v1/value?indicator=aqi_good_days_share&place=us-county-01127Questions
What is the share of days with good air quality (US EPA AQI) in Walker County?
Share of days with good air quality (US EPA AQI) in Walker County was 40.2% in 2011, according to EPA. That is up 9.2 pts from 2010.
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 Walker County?
100% in 1992, the highest value since 1990 in this series.