Data / Rankings / Median Air Quality Index (US EPA) / Counties in Nevada

Counties in Nevada by median Air Quality Index (US EPA)

Clark County had the highest median Air Quality Index (US EPA) of 9 counties in 2015, at 61. Nye County had the lowest, at 16. The median was 44. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest61Clark County
Lowest16Nye County
Median449 counties

Map of counties, 2015

Churchill County: 44 indexClark County: 61 indexDouglas County: 41 indexElko County: 30 indexLyon County: 45 indexNye County: 16 indexWashoe County: 52 indexWhite Pine County: 42 indexCarson City: 44 index
  • Under 37
  • 37 to 42
  • 42 to 44
  • 44 to 48
  • 48 and over
  • No data
index, 2015. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2015

Clark County: 61 indexClark County61Washoe County: 52 indexWashoe County52Lyon County: 45 indexLyon County45Carson City: 44 indexCarson City44Churchill County: 44 indexChurchill County44White Pine County: 42 indexWhite Pine County42Douglas County: 41 indexDouglas County41Elko County: 30 indexElko County30Nye County: 16 indexNye County16Clark County: 61 indexClark County61Washoe County: 52 indexWashoe County52Lyon County: 45 indexLyon County45Carson City: 44 indexCarson City44Churchill County: 44 indexChurchill County44White Pine County: 42 indexWhite Pine County42Douglas County: 41 indexDouglas County41Elko County: 30 indexElko County30Nye County: 16 indexNye County16
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2015
index		Change on 2014
1Clark County610
2Washoe County52-2
3Lyon County45-2
4Carson City44-2
4Churchill County44-2
6White Pine County42-1
7Douglas County41+4
8Elko County30-2
9Nye County16-4

Other periods

About this ranking

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.

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 2015 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: 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 (Counties in Nevada by median Air Quality Index (US EPA), 2015) [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, Counties in Nevada by median Air Quality Index (US EPA), 2015. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/nevada-counties?period=2015. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Nevada by median Air Quality Index (US EPA), 2015. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/nevada-counties?period=2015.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Nevada by median Air Quality Index (US EPA), 2015 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/nevada-counties?period=2015 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_nevada_by_2015,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: median daily AQI: Counties in Nevada by median Air Quality Index (US EPA), 2015}},
  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/median-air-quality-index/nevada-counties?period=2015. 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: Counties in Nevada by median Air Quality Index (US EPA), 2015
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/median-air-quality-index/nevada-counties?period=2015
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/nevada-counties?period=2015.
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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Rank Counties in Nevada by median Air Quality Index (US EPA) using official data, and cite the source.
rank_places {"indicator":"aqi_median","level":"province","within":"Nevada","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=aqi_median&level=province&within=Nevada&limit=10

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Questions

Which county has the highest median Air Quality Index (US EPA)?

Clark County, with 61 in 2015, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Nye County, with 16 in 2015.

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: median daily AQI. Retrieved 2026-10-12. 3 counties have no value for 2015 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Nevada: more rankings