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

East Baton Rouge Parish had the highest share of days unhealthy for sensitive groups or worse (US EPA AQI) of 26 counties in 2000, at 17.8%. Terrebonne Parish had the lowest, at 0%. The median was 8.2%. Source: EPA.

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Median8.226 counties

Map of counties, 2000

Ascension Parish: 9.6 %Beauregard Parish: 5.5 %Bossier Parish: 7.7 %Caddo Parish: 8.5 %Calcasieu Parish: 12 %Concordia Parish: 0 %East Baton Rouge Parish: 17.8 %Grant Parish: 7 %Iberville Parish: 15 %Jefferson Parish: 12.6 %Lafayette Parish: 9.1 %Lafourche Parish: 11.3 %Livingston Parish: 13.2 %Orleans Parish: 6 %Ouachita Parish: 9.3 %Plaquemines Parish: 0 %Pointe Coupee Parish: 4.1 %Rapides Parish: 0 %St. Bernard Parish: 7.5 %St. Charles Parish: 8.7 %St. James Parish: 7.4 %St. John the Baptist Parish: 10.5 %St. Mary Parish: 7.8 %Tangipahoa Parish: 1.7 %Terrebonne Parish: 0 %West Baton Rouge Parish: 13.4 %
  • Under 4.1
  • 4.1 to 7.5
  • 7.5 to 9.1
  • 9.1 to 12
  • 12 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

East Baton Rouge Parish: 17.8 %East Baton Rouge Parish17.8Iberville Parish: 15 %Iberville Parish15West Baton Rouge Parish: 13.4 %West Baton Rouge Parish13.4Livingston Parish: 13.2 %Livingston Parish13.2Jefferson Parish: 12.6 %Jefferson Parish12.6Calcasieu Parish: 12 %Calcasieu Parish12Lafourche Parish: 11.3 %Lafourche Parish11.3St. John the Baptist Parish: 10.5 %St. John the Baptist Parish10.5Ascension Parish: 9.6 %Ascension Parish9.6Ouachita Parish: 9.3 %Ouachita Parish9.3Lafayette Parish: 9.1 %Lafayette Parish9.1St. Charles Parish: 8.7 %St. Charles Parish8.7Caddo Parish: 8.5 %Caddo Parish8.5St. Mary Parish: 7.8 %St. Mary Parish7.8Bossier Parish: 7.7 %Bossier Parish7.7St. Bernard Parish: 7.5 %St. Bernard Parish7.5St. James Parish: 7.4 %St. James Parish7.4Grant Parish: 7 %Grant Parish7Orleans Parish: 6 %Orleans Parish6Beauregard Parish: 5.5 %Beauregard Parish5.5Pointe Coupee Parish: 4.1 %Pointe Coupee Parish4.1Tangipahoa Parish: 1.7 %Tangipahoa Parish1.7Concordia Parish: 0 %Concordia Parish0Plaquemines Parish: 0 %Plaquemines Parish0Rapides Parish: 0 %Rapides Parish0Terrebonne Parish: 0 %Terrebonne Parish0East Baton Rouge Parish: 17.8 %East Baton Rouge Parish17.8Iberville Parish: 15 %Iberville Parish15West Baton Rouge Parish: 13.4 %West Baton Rouge Parish13.4Livingston Parish: 13.2 %Livingston Parish13.2Jefferson Parish: 12.6 %Jefferson Parish12.6Calcasieu Parish: 12 %Calcasieu Parish12Lafourche Parish: 11.3 %Lafourche Parish11.3St. John the Baptist Parish: 10.5 %St. John the Baptist Parish10.5Ascension Parish: 9.6 %Ascension Parish9.6Ouachita Parish: 9.3 %Ouachita Parish9.3Lafayette Parish: 9.1 %Lafayette Parish9.1St. Charles Parish: 8.7 %St. Charles Parish8.7Caddo Parish: 8.5 %Caddo Parish8.5St. Mary Parish: 7.8 %St. Mary Parish7.8Bossier Parish: 7.7 %Bossier Parish7.7St. Bernard Parish: 7.5 %St. Bernard Parish7.5St. James Parish: 7.4 %St. James Parish7.4Grant Parish: 7 %Grant Parish7Orleans Parish: 6 %Orleans Parish6Beauregard Parish: 5.5 %Beauregard Parish5.5Pointe Coupee Parish: 4.1 %Pointe Coupee Parish4.1Tangipahoa Parish: 1.7 %Tangipahoa Parish1.7Concordia Parish: 0 %Concordia Parish0Plaquemines Parish: 0 %Plaquemines Parish0Rapides Parish: 0 %Rapides Parish0Terrebonne Parish: 0 %Terrebonne Parish0
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2000 (%)Change on 1999
1East Baton Rouge Parish17.8+2.2 pts
2Iberville Parish15+2.1 pts
3West Baton Rouge Parish13.4+7.9 pts
4Livingston Parish13.2+2.5 pts
5Jefferson Parish12.6+0.8 pts
6Calcasieu Parish12+3.5 pts
7Lafourche Parish11.3+0.2 pts
8St. John the Baptist Parish10.5+1.5 pts
9Ascension Parish9.6+4.1 pts
10Ouachita Parish9.3+1.9 pts
11Lafayette Parish9.1+1.7 pts
12St. Charles Parish8.7+1.1 pts
13Caddo Parish8.5-2.8 pts
14St. Mary Parish7.8+0.7 pts
15Bossier Parish7.7-3 pts
16St. Bernard Parish7.5-1.6 pts
17St. James Parish7.4-0.6 pts
18Grant Parish7-3.4 pts
19Orleans Parish6+2.7 pts
20Beauregard Parish5.5+0.3 pts
21Pointe Coupee Parish4.1-0.8 pts
22Tangipahoa Parish1.7-1.7 pts
23Concordia Parish00 pts
23Plaquemines Parish0n/a
23Rapides Parish0-1.8 pts
23Terrebonne Parish0n/a

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. 4 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 Louisiana 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 Louisiana 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/louisiana-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 Louisiana 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/louisiana-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 Louisiana 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/louisiana-counties?period=2000 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_louisiana_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 Louisiana 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/louisiana-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 Louisiana 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/louisiana-counties?period=2000
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/louisiana-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 Louisiana 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)?

East Baton Rouge Parish, with 17.8% in 2000, according to EPA.

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

Terrebonne Parish, with 0% 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. 4 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 Louisiana: more rankings