Counties in Mississippi by share of days with good air quality (US EPA AQI)

Yalobusha County had the highest share of days with good air quality (US EPA AQI) of 19 counties in 2001, at 75.9%. Harrison County had the lowest, at 25.3%. The median was 54.5%. Source: EPA.

Highest75.9Yalobusha County

Lowest25.3Harrison County

Median54.519 counties

Map of counties, 2001

Under 30
30 to 51
51 to 57
57 to 61
61 and over
No data

%, 2001. 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, 2001

%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2001 (%)	Change on 2000
1	Yalobusha County	75.9	+12.4 pts
2	Hancock County	69.7	+13.3 pts
3	Madison County	68.2	+19.4 pts
4	Hinds County	61.1	+6.2 pts
5	DeSoto County	60.5	+9.7 pts
6	Adams County	59.9	+17 pts
7	Warren County	59.2	+15.1 pts
8	Jackson County	57.3	+14.5 pts
9	Bolivar County	56.1	+14.7 pts
10	Lauderdale County	54.5	+19.3 pts
11	Alcorn County	54.2	n/a
12	Lee County	49.8	+13 pts
13	Scott County	39.1	+6.3 pts
14	Pearl River County	38.8	+14.4 pts
15	Lowndes County	30.2	+7.1 pts
16	Forrest County	28.7	+8.5 pts
17	Jones County	28.3	+13.9 pts
18	Rankin County	28.2	+5.9 pts
19	Harrison County	25.3	+1.4 pts

Other periods

About this ranking

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.

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 2001 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: 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

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: good days as a share of days with an AQI, calculated with stored counts (Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001) [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, Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/mississippi-counties?period=2001. 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. Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/mississippi-counties?period=2001.

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, Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/mississippi-counties?period=2001 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_mississippi_by_2001,
  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: Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001}},
  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/good-air-quality-days-share/mississippi-counties?period=2001. 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: Counties in Mississippi by share of days with good air quality (US EPA AQI), 2001
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/good-air-quality-days-share/mississippi-counties?period=2001
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/mississippi-counties?period=2001.
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  -

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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Yalobusha County, with 75.9% in 2001, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Harrison County, with 25.3% in 2001.

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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 10 counties have no value for 2001 and are not ranked.