Counties in Alabama by highest daily Air Quality Index (US EPA)

Mobile County had the highest highest daily Air Quality Index (US EPA) of 24 counties in 2003, at 182. Marengo County had the lowest, at 36. The median was 143. Source: the U.S. Environmental Protection Agency.

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Highest182Mobile County
Median14324 counties

Map of counties, 2003

Baldwin County: 174 indexBarbour County: 85 indexClay County: 159 indexColbert County: 151 indexDeKalb County: 164 indexElmore County: 143 indexEscambia County: 92 indexEtowah County: 143 indexHouston County: 144 indexJefferson County: 177 indexLawrence County: 169 indexLimestone County: 159 indexMadison County: 143 indexMarengo County: 36 indexMobile County: 182 indexMontgomery County: 119 indexMorgan County: 161 indexPike County: 76 indexRussell County: 115 indexShelby County: 156 indexSumter County: 99 indexTalladega County: 116 indexTuscaloosa County: 119 indexWalker County: 106 index
  • Under 100
  • 100 to 120
  • 120 to 150
  • 150 to 160
  • 160 and over
  • No data
index, 2003. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2003

Mobile County: 182 indexMobile County182Jefferson County: 177 indexJefferson County177Baldwin County: 174 indexBaldwin County174Lawrence County: 169 indexLawrence County169DeKalb County: 164 indexDeKalb County164Morgan County: 161 indexMorgan County161Clay County: 159 indexClay County159Limestone County: 159 indexLimestone County159Shelby County: 156 indexShelby County156Colbert County: 151 indexColbert County151Houston County: 144 indexHouston County144Elmore County: 143 indexElmore County143Etowah County: 143 indexEtowah County143Madison County: 143 indexMadison County143Montgomery County: 119 indexMontgomery County119Tuscaloosa County: 119 indexTuscaloosa County119Talladega County: 116 indexTalladega County116Russell County: 115 indexRussell County115Walker County: 106 indexWalker County106Sumter County: 99 indexSumter County99Escambia County: 92 indexEscambia County92Barbour County: 85 indexBarbour County85Pike County: 76 indexPike County76Marengo County: 36 indexMarengo County36Mobile County: 182 indexMobile County182Jefferson County: 177 indexJefferson County177Baldwin County: 174 indexBaldwin County174Lawrence County: 169 indexLawrence County169DeKalb County: 164 indexDeKalb County164Morgan County: 161 indexMorgan County161Clay County: 159 indexClay County159Limestone County: 159 indexLimestone County159Shelby County: 156 indexShelby County156Colbert County: 151 indexColbert County151Houston County: 144 indexHouston County144Elmore County: 143 indexElmore County143Etowah County: 143 indexEtowah County143Madison County: 143 indexMadison County143Montgomery County: 119 indexMontgomery County119Tuscaloosa County: 119 indexTuscaloosa County119Talladega County: 116 indexTalladega County116Russell County: 115 indexRussell County115Walker County: 106 indexWalker County106Sumter County: 99 indexSumter County99Escambia County: 92 indexEscambia County92Barbour County: 85 indexBarbour County85Pike County: 76 indexPike County76Marengo County: 36 indexMarengo County36
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Other periods

About this ranking

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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 7 counties with data in other periods have no value for 2003 and are left out rather than filled from another source. Equal values share a rank.

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 (Counties in Alabama by highest daily Air Quality Index (US EPA), 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, Counties in Alabama by highest daily Air Quality Index (US EPA), 2003. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/alabama-counties?period=2003. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Alabama by highest daily Air Quality Index (US EPA), 2003. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/alabama-counties?period=2003.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Alabama by highest daily Air Quality Index (US EPA), 2003 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/alabama-counties?period=2003 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_alabama_by_2003,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Alabama by highest daily Air Quality Index (US EPA), 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/rankings/highest-daily-air-quality-index/alabama-counties?period=2003. 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: Counties in Alabama by highest daily Air Quality Index (US EPA), 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/rankings/highest-daily-air-quality-index/alabama-counties?period=2003
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/alabama-counties?period=2003.
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  - 
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Rank Counties in Alabama by highest daily Air Quality Index (US EPA) using official data, and cite the source.
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Questions

Which county has the highest highest daily Air Quality Index (US EPA)?

Mobile County, with 182 in 2003, according to the U.S. Environmental Protection Agency.

Which county has the lowest highest daily Air Quality Index (US EPA)?

Marengo County, with 36 in 2003.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12. 7 counties have no value for 2003 and are not ranked.

Highest daily Air Quality Index (US EPA): other rankings

Counties in Alabama: more rankings