Data / Rankings / Share of days unhealthy for sensitive groups or worse (US EPA AQI) / Counties in Mississippi

Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI)

Lee County had the highest share of days unhealthy for sensitive groups or worse (US EPA AQI) of 18 counties in 2000, at 15.1%. Scott County had the lowest, at 0.8%. The median was 9.9%. Source: EPA.

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Highest15.1Lee County
Lowest0.8Scott County
Median9.918 counties

Map of counties, 2000

Adams County: 12.1 %Bolivar County: 14 %DeSoto County: 13.7 %Forrest County: 0.8 %Hancock County: 12.2 %Harrison County: 12.9 %Hinds County: 6.3 %Jackson County: 14.1 %Jones County: 1.7 %Lauderdale County: 10.7 %Lee County: 15.1 %Lowndes County: 0.9 %Madison County: 11.1 %Pearl River County: 1.3 %Rankin County: 1 %Scott County: 0.8 %Warren County: 9 %Yalobusha County: 8.3 %
  • Under 1.1
  • 1.1 to 7.9
  • 7.9 to 11
  • 11 to 13
  • 13 and over
  • No data
%, 2000. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2000

Lee County: 15.1 %Lee County15.1Jackson County: 14.1 %Jackson County14.1Bolivar County: 14 %Bolivar County14DeSoto County: 13.7 %DeSoto County13.7Harrison County: 12.9 %Harrison County12.9Hancock County: 12.2 %Hancock County12.2Adams County: 12.1 %Adams County12.1Madison County: 11.1 %Madison County11.1Lauderdale County: 10.7 %Lauderdale County10.7Warren County: 9 %Warren County9Yalobusha County: 8.3 %Yalobusha County8.3Hinds County: 6.3 %Hinds County6.3Jones County: 1.7 %Jones County1.7Pearl River County: 1.3 %Pearl River County1.3Rankin County: 1 %Rankin County1Lowndes County: 0.9 %Lowndes County0.9Forrest County: 0.8 %Forrest County0.8Scott County: 0.8 %Scott County0.8Lee County: 15.1 %Lee County15.1Jackson County: 14.1 %Jackson County14.1Bolivar County: 14 %Bolivar County14DeSoto County: 13.7 %DeSoto County13.7Harrison County: 12.9 %Harrison County12.9Hancock County: 12.2 %Hancock County12.2Adams County: 12.1 %Adams County12.1Madison County: 11.1 %Madison County11.1Lauderdale County: 10.7 %Lauderdale County10.7Warren County: 9 %Warren County9Yalobusha County: 8.3 %Yalobusha County8.3Hinds County: 6.3 %Hinds County6.3Jones County: 1.7 %Jones County1.7Pearl River County: 1.3 %Pearl River County1.3Rankin County: 1 %Rankin County1Lowndes County: 0.9 %Lowndes County0.9Forrest County: 0.8 %Forrest County0.8Scott County: 0.8 %Scott County0.8
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2000 (%)Change on 1999
1Lee County15.1-6.7 pts
2Jackson County14.1+2.2 pts
3Bolivar County14-9.8 pts
4DeSoto County13.7+1.1 pts
5Harrison County12.9-1.8 pts
6Hancock County12.2-1.4 pts
7Adams County12.1-4.1 pts
8Madison County11.1+0.4 pts
9Lauderdale County10.7-2.1 pts
10Warren County9+2.7 pts
11Yalobusha County8.3-3.6 pts
12Hinds County6.30 pts
13Jones County1.7-0.2 pts
14Pearl River County1.3n/a
15Rankin County10 pts
16Lowndes County0.9-2.2 pts
17Forrest County0.8-1.2 pts
17Scott County0.8+0.8 pts

Other periods

About this ranking

Days with a daily Air Quality Index above 100 (unhealthy for sensitive groups, unhealthy, very unhealthy or hazardous) 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; the counts are stored with each value.

Use the share rather than the number of days to compare counties, since the days with an AQI differ. 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. 11 counties with data in other periods have no value for 2000 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: days with an AQI above 100 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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts (Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000) [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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/mississippi-counties?period=2000. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/mississippi-counties?period=2000.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/unhealthy-air-quality-days-share/mississippi-counties?period=2000 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_mississippi_by_2000,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000}},
  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/unhealthy-air-quality-days-share/mississippi-counties?period=2000. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2000
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/unhealthy-air-quality-days-share/mississippi-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/mississippi-counties?period=2000.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 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  -
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Rank Counties in Mississippi by share of days unhealthy for sensitive groups or worse (US EPA AQI) using official data, and cite the source.
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Questions

Which county has the highest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Lee County, with 15.1% in 2000, according to EPA.

Which county has the lowest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Scott County, with 0.8% in 2000.

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: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 11 counties have no value for 2000 and are not ranked.

Share of days unhealthy for sensitive groups or worse (US EPA AQI): other rankings

Counties in Mississippi: more rankings