Data / Median Air Quality Index (US EPA) / Nassau County

Median Air Quality Index (US EPA) in Nassau County

Median Air Quality Index (US EPA) in Nassau County was 42 in 2020, according to the U.S. Environmental Protection Agency. That is up 1 from 2019.

2020, index42
Change on 2019+1
Series high482014
Series low162006

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Median Air Quality Index (US EPA) in Nassau County, 1993 to 2020

10203040501993199720012005201520201993: 24 index1994: 21 index1995: 21 index1996: 22 index1997: 23 index1998: 22 index1999: 24 index2000: 22 index2001: 22 index2002: 19 index2003: 20 index2004: 24 index2005: 22 index2006: 16 index2013: 43 index2014: 48 index2015: 43 index2016: 45 index2017: 47 index2018: 43 index2019: 41 index2020: 42 index10203040501993200120201993: 24 index1994: 21 index1995: 21 index1996: 22 index1997: 23 index1998: 22 index1999: 24 index2000: 22 index2001: 22 index2002: 19 index2003: 20 index2004: 24 index2005: 22 index2006: 16 index2013: 43 index2014: 48 index2015: 43 index2016: 45 index2017: 47 index2018: 43 index2019: 41 index2020: 42 index
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 22 values
Periodindex
202042
201941
201843
201747
201645
201543
201448
201343
200616
200522
200424
200320
200219
200122
200022
199924
199822
199723
199622
199521
199421
199324

Nassau County compared with nearby places

Alachua County: 42 indexBaker County: 40 indexBay County: 47 indexBrevard County: 43 indexBroward County: 49 indexCitrus County: 43 indexCollier County: 41 indexColumbia County: 44 indexDuval County: 52 indexEscambia County: 51 indexFlagler County: 31 indexHamilton County: 46 indexHighlands County: 31 indexHillsborough County: 52 indexHolmes County: 47 indexIndian River County: 37 indexLake County: 32 indexLee County: 39 indexLeon County: 49 indexLiberty County: 31 indexManatee County: 33 indexMarion County: 46 indexMartin County: 42 indexMiami-Dade County: 45 indexNassau County: 42 indexOkaloosa County: 34 indexOrange County: 34 indexOsceola County: 32 indexPalm Beach County: 42 indexPasco County: 35 indexPinellas County: 46 indexPolk County: 42 indexPutnam County: 14 indexSt. Lucie County: 33 indexSanta Rosa County: 47 indexSarasota County: 44 indexSeminole County: 40 indexVolusia County: 44 indexWakulla County: 41 index
  • Under 33
  • 33 to 40
  • 40 to 42
  • 42 to 44
  • 44 to 47
  • 47 and over
  • No data
Median Air Quality Index (US EPA), 2020, index. Nassau County is outlined. Same source and period for every area shown. Source: U.S. Environmental Protection Agency. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

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.

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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 (Median Air Quality Index (US EPA), Nassau County, 1993 to 2020) [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, Median Air Quality Index (US EPA), Nassau County, 1993 to 2020. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/median-air-quality-index/nassau-county-florida. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Median Air Quality Index (US EPA), Nassau County, 1993 to 2020. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/median-air-quality-index/nassau-county-florida.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Median Air Quality Index (US EPA), Nassau County, 1993 to 2020 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/median-air-quality-index/nassau-county-florida (Accessed: 12 October 2026).

BibTeX
@misc{environmental_median_air_quality_index_2020,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Median Air Quality Index (US EPA), Nassau County, 1993 to 2020}},
  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/en/median-air-quality-index/nassau-county-florida. 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: Median Air Quality Index (US EPA), Nassau County, 1993 to 2020
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/en/median-air-quality-index/nassau-county-florida
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/median-air-quality-index/nassau-county-florida.
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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Questions

What is the median Air Quality Index (US EPA) in Nassau County?

Median Air Quality Index (US EPA) in Nassau County was 42 in 2020, according to the U.S. Environmental Protection Agency. That is up 1 from 2019.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: median daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest median Air Quality Index (US EPA) in Nassau County?

48 in 2014, the highest value since 1993 in this series.

Related statistics for Nassau County

All statistics for Nassau County | Nassau County in figures