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

Median Air Quality Index (US EPA) in Walker County

Median Air Quality Index (US EPA) in Walker County was 53 in 2011, according to the U.S. Environmental Protection Agency. That is down 1 from 2010.

2011, index53
Change on 2010-1
Series high651999
Series low181997

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 Walker County, 1990 to 2011

1020304050607019901993199619992003200620111990: 23 index1991: 23 index1992: 22 index1993: 23 index1994: 21 index1995: 23 index1996: 19 index1997: 18 index1998: 19 index1999: 65 index2000: 61 index2002: 43 index2003: 58 index2004: 56 index2005: 58 index2006: 58 index2007: 59 index2008: 56 index2009: 52 index2010: 54 index2011: 53 index02040608019901997200520111990: 23 index1991: 23 index1992: 22 index1993: 23 index1994: 21 index1995: 23 index1996: 19 index1997: 18 index1998: 19 index1999: 65 index2000: 61 index2002: 43 index2003: 58 index2004: 56 index2005: 58 index2006: 58 index2007: 59 index2008: 56 index2009: 52 index2010: 54 index2011: 53 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 21 values
Periodindex
201153
201054
200952
200856
200759
200658
200558
200456
200358
200243
200061
199965
199819
199718
199619
199523
199421
199323
199222
199123
199023

Walker County compared with nearby places

Baldwin County: 44 indexClay County: 52 indexColbert County: 44 indexDeKalb County: 42 indexElmore County: 44 indexEtowah County: 44 indexHouston County: 46 indexJefferson County: 61 indexLawrence County: 46 indexMadison County: 46 indexMobile County: 45 indexMontgomery County: 48 indexMorgan County: 46 indexRussell County: 49 indexShelby County: 47 indexSumter County: 38 indexTalladega County: 55 indexTuscaloosa County: 40 indexWalker County: 53 index
  • Under 44
  • 44 to 45
  • 45 to 46
  • 46 to 50
  • 50 and over
  • No data
Median Air Quality Index (US EPA), 2011, index. Walker 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), 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: median daily AQI, Median Air Quality Index (US EPA), 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/median-air-quality-index/walker-county-alabama. 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), 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/median-air-quality-index/walker-county-alabama.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Walker County, 1990 to 2011 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/median-air-quality-index/walker-county-alabama (Accessed: 12 October 2026).

BibTeX
@misc{environmental_median_air_quality_index_2011,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Median Air Quality Index (US EPA), 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/median-air-quality-index/walker-county-alabama. 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), 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/median-air-quality-index/walker-county-alabama
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/walker-county-alabama.
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 Walker County?

Median Air Quality Index (US EPA) in Walker County was 53 in 2011, according to the U.S. Environmental Protection Agency. That is down 1 from 2010.

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 Walker County?

65 in 1999, the highest value since 1990 in this series.

Related statistics for Walker County

All statistics for Walker County | Walker County in figures