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

Hillsborough County had the highest share of days unhealthy for sensitive groups or worse (US EPA AQI) of 39 counties in 2014, at 1.6%. Seminole County had the lowest, at 0%. The median was 0.3%. Source: EPA.

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Median0.339 counties

Map of counties, 2014

Alachua County: 0 %Baker County: 0 %Bay County: 0 %Brevard County: 0 %Broward County: 0.5 %Citrus County: 0 %Collier County: 0 %Columbia County: 0 %Duval County: 1.1 %Escambia County: 1.1 %Flagler County: 0 %Hamilton County: 0 %Highlands County: 0 %Hillsborough County: 1.6 %Holmes County: 0 %Indian River County: 0.3 %Lake County: 0.6 %Lee County: 0 %Leon County: 0.3 %Liberty County: 0 %Manatee County: 0.3 %Marion County: 0 %Martin County: 0.3 %Miami-Dade County: 0.3 %Nassau County: 0 %Okaloosa County: 0.3 %Orange County: 0.3 %Osceola County: 0 %Palm Beach County: 0.5 %Pasco County: 0.3 %Pinellas County: 0.3 %Polk County: 0 %Putnam County: 0 %St. Lucie County: 0.3 %Santa Rosa County: 0.8 %Sarasota County: 0.3 %Seminole County: 0 %Volusia County: 0.3 %Wakulla County: 0.3 %
  • Under 0.3
  • 0.3 to 0.4
  • 0.4 and over
  • No data
%, 2014. 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, 2014

Hillsborough County: 1.6 %Hillsborough County1.6Duval County: 1.1 %Duval County1.1Escambia County: 1.1 %Escambia County1.1Santa Rosa County: 0.8 %Santa Rosa County0.8Lake County: 0.6 %Lake County0.6Broward County: 0.5 %Broward County0.5Palm Beach County: 0.5 %Palm Beach County0.5Indian River County: 0.3 %Indian River County0.3Leon County: 0.3 %Leon County0.3Manatee County: 0.3 %Manatee County0.3Martin County: 0.3 %Martin County0.3Miami-Dade County: 0.3 %Miami-Dade County0.3Okaloosa County: 0.3 %Okaloosa County0.3Orange County: 0.3 %Orange County0.3Pasco County: 0.3 %Pasco County0.3Pinellas County: 0.3 %Pinellas County0.3Sarasota County: 0.3 %Sarasota County0.3St. Lucie County: 0.3 %St. Lucie County0.3Volusia County: 0.3 %Volusia County0.3Wakulla County: 0.3 %Wakulla County0.3Alachua County: 0 %Alachua County0Baker County: 0 %Baker County0Bay County: 0 %Bay County0Brevard County: 0 %Brevard County0Citrus County: 0 %Citrus County0Collier County: 0 %Collier County0Columbia County: 0 %Columbia County0Flagler County: 0 %Flagler County0Hamilton County: 0 %Hamilton County0Highlands County: 0 %Highlands County0Holmes County: 0 %Holmes County0Lee County: 0 %Lee County0Liberty County: 0 %Liberty County0Marion County: 0 %Marion County0Nassau County: 0 %Nassau County0Osceola County: 0 %Osceola County0Polk County: 0 %Polk County0Putnam County: 0 %Putnam County0Seminole County: 0 %Seminole County0Hillsborough County: 1.6 %Hillsborough County1.6Duval County: 1.1 %Duval County1.1Escambia County: 1.1 %Escambia County1.1Santa Rosa County: 0.8 %Santa Rosa County0.8Lake County: 0.6 %Lake County0.6Broward County: 0.5 %Broward County0.5Palm Beach County: 0.5 %Palm Beach County0.5Indian River County: 0.3 %Indian River County0.3Leon County: 0.3 %Leon County0.3Manatee County: 0.3 %Manatee County0.3Martin County: 0.3 %Martin County0.3Miami-Dade County: 0.3 %Miami-Dade County0.3Okaloosa County: 0.3 %Okaloosa County0.3Orange County: 0.3 %Orange County0.3Pasco County: 0.3 %Pasco County0.3Pinellas County: 0.3 %Pinellas County0.3Sarasota County: 0.3 %Sarasota County0.3St. Lucie County: 0.3 %St. Lucie County0.3Volusia County: 0.3 %Volusia County0.3Wakulla County: 0.3 %Wakulla County0.3Alachua County: 0 %Alachua County0Baker County: 0 %Baker County0Bay County: 0 %Bay County0Brevard County: 0 %Brevard County0Citrus County: 0 %Citrus County0Collier County: 0 %Collier County0Columbia County: 0 %Columbia County0Flagler County: 0 %Flagler County0Hamilton County: 0 %Hamilton County0Highlands County: 0 %Highlands County0Holmes County: 0 %Holmes County0Lee County: 0 %Lee County0Liberty County: 0 %Liberty County0Marion County: 0 %Marion County0Nassau County: 0 %Nassau County0Osceola County: 0 %Osceola County0Polk County: 0 %Polk County0Putnam County: 0 %Putnam County0Seminole County: 0 %Seminole County0
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2014 (%)Change on 2013
1Hillsborough County1.6+0.8 pts
2Duval County1.1+0.8 pts
2Escambia County1.1+0.8 pts
4Santa Rosa County0.8+0.8 pts
5Lake County0.6+0.3 pts
6Broward County0.5+0.2 pts
6Palm Beach County0.50 pts
8Indian River County0.3+0.3 pts
8Leon County0.3-0.5 pts
8Manatee County0.3-0.2 pts
8Martin County0.3+0.3 pts
8Miami-Dade County0.3-0.2 pts
8Okaloosa County0.3+0.3 pts
8Orange County0.30 pts
8Pasco County0.30 pts
8Pinellas County0.3-0.5 pts
8Sarasota County0.3-0.8 pts
8St. Lucie County0.3n/a
8Volusia County0.3+0.3 pts
8Wakulla County0.3+0.3 pts
21Alachua County00 pts
21Baker County00 pts
21Bay County0-0.5 pts
21Brevard County00 pts
21Citrus County00 pts
21Collier County00 pts
21Columbia County00 pts
21Flagler County00 pts
21Hamilton County00 pts
21Highlands County00 pts
21Holmes County00 pts
21Lee County00 pts
21Liberty County00 pts
21Marion County00 pts
21Nassau County00 pts
21Osceola County0-0.3 pts
21Polk County0-0.3 pts
21Putnam County00 pts
21Seminole County00 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. 3 counties with data in other periods have no value for 2014 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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014) [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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014. 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/florida-counties?period=2014. 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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014. 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/florida-counties?period=2014.

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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/unhealthy-air-quality-days-share/florida-counties?period=2014 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_florida_by_2014,
  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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014}},
  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/florida-counties?period=2014. 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 Florida by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2014
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/florida-counties?period=2014
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/florida-counties?period=2014.
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 Florida 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)?

Hillsborough County, with 1.6% in 2014, according to EPA.

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

Seminole County, with 0% in 2014.

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. 3 counties have no value for 2014 and are not ranked.

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

Counties in Florida: more rankings