Data / Rankings / Median Air Quality Index (US EPA) / Counties in Mississippi

Counties in Mississippi by median Air Quality Index (US EPA), 2005

Harrison County had the highest median Air Quality Index (US EPA) of 19 counties in 2005, at 60. Marshall County had the lowest, at 30. The median was 55. Source: the U.S. Environmental Protection Agency.

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Highest60Harrison County
Lowest30Marshall County
Median5519 counties

Map of counties, 2005

Adams County: 50 indexBolivar County: 56 indexDeSoto County: 53 indexForrest County: 58 indexGrenada County: 57 indexHancock County: 55 indexHarrison County: 60 indexHinds County: 59 indexJackson County: 52 indexJones County: 60 indexLauderdale County: 50 indexLee County: 58 indexLowndes County: 56 indexMarshall County: 30 indexPearl River County: 55 indexRankin County: 46 indexScott County: 55 indexWarren County: 55 indexYalobusha County: 39 index
  • Under 50
  • 50 to 55
  • 55 to 56
  • 56 to 58
  • 58 and over
  • No data
index, 2005. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2005

Harrison County: 60 indexHarrison County60Jones County: 60 indexJones County60Hinds County: 59 indexHinds County59Forrest County: 58 indexForrest County58Lee County: 58 indexLee County58Grenada County: 57 indexGrenada County57Bolivar County: 56 indexBolivar County56Lowndes County: 56 indexLowndes County56Hancock County: 55 indexHancock County55Pearl River County: 55 indexPearl River County55Scott County: 55 indexScott County55Warren County: 55 indexWarren County55DeSoto County: 53 indexDeSoto County53Jackson County: 52 indexJackson County52Adams County: 50 indexAdams County50Lauderdale County: 50 indexLauderdale County50Rankin County: 46 indexRankin County46Yalobusha County: 39 indexYalobusha County39Marshall County: 30 indexMarshall County30Harrison County: 60 indexHarrison County60Jones County: 60 indexJones County60Hinds County: 59 indexHinds County59Forrest County: 58 indexForrest County58Lee County: 58 indexLee County58Grenada County: 57 indexGrenada County57Bolivar County: 56 indexBolivar County56Lowndes County: 56 indexLowndes County56Hancock County: 55 indexHancock County55Pearl River County: 55 indexPearl River County55Scott County: 55 indexScott County55Warren County: 55 indexWarren County55DeSoto County: 53 indexDeSoto County53Jackson County: 52 indexJackson County52Adams County: 50 indexAdams County50Lauderdale County: 50 indexLauderdale County50Rankin County: 46 indexRankin County46Yalobusha County: 39 indexYalobusha County39Marshall County: 30 indexMarshall County30
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2005
index		Change on 2004
1Harrison County60+4
1Jones County60+2
3Hinds County59+2
4Forrest County58+2
4Lee County58+2
6Grenada County57+4
7Bolivar County56+2
7Lowndes County56+1
9Hancock County55+15
9Pearl River County55+2
9Scott County55+2
9Warren County55+4
13DeSoto County53+6
14Jackson County52+9
15Adams County50+5
15Lauderdale County50+4
17Rankin County46-8
18Yalobusha County39+3
19Marshall County30-8

Other periods

About this ranking

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.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 10 counties with data in other periods have no value for 2005 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: 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 (Counties in Mississippi by median Air Quality Index (US EPA), 2005) [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, Counties in Mississippi by median Air Quality Index (US EPA), 2005. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/mississippi-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Mississippi by median Air Quality Index (US EPA), 2005. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/mississippi-counties.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Mississippi by median Air Quality Index (US EPA), 2005 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/mississippi-counties (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_mississippi_by_2005,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Mississippi by median Air Quality Index (US EPA), 2005}},
  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/median-air-quality-index/mississippi-counties. 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: Counties in Mississippi by median Air Quality Index (US EPA), 2005
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/median-air-quality-index/mississippi-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/mississippi-counties.
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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Rank Counties in Mississippi by median Air Quality Index (US EPA) using official data, and cite the source.
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Questions

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

Harrison County, with 60 in 2005, according to the U.S. Environmental Protection Agency.

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

Marshall County, with 30 in 2005.

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: median daily AQI. Retrieved 2026-10-12. 10 counties have no value for 2005 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Mississippi: more rankings