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

Counties in Nevada by median Air Quality Index (US EPA), 2025

Clark County had the highest median Air Quality Index (US EPA) of 9 counties in 2025, at 61. Douglas County had the lowest, at 22. The median was 42. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest61Clark County
Lowest22Douglas County
Median429 counties

Map of counties, 2025

Churchill County: 40 indexClark County: 61 indexDouglas County: 22 indexElko County: 42 indexLyon County: 41 indexNye County: 26 indexWashoe County: 50 indexWhite Pine County: 45 indexCarson City: 42 index
  • Under 34
  • 34 to 41
  • 41 to 42
  • 42 to 47
  • 47 and over
  • No data
index, 2025. 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, 2025

Clark County: 61 indexClark County61Washoe County: 50 indexWashoe County50White Pine County: 45 indexWhite Pine County45Carson City: 42 indexCarson City42Elko County: 42 indexElko County42Lyon County: 41 indexLyon County41Churchill County: 40 indexChurchill County40Nye County: 26 indexNye County26Douglas County: 22 indexDouglas County22Clark County: 61 indexClark County61Washoe County: 50 indexWashoe County50White Pine County: 45 indexWhite Pine County45Carson City: 42 indexCarson City42Elko County: 42 indexElko County42Lyon County: 41 indexLyon County41Churchill County: 40 indexChurchill County40Nye County: 26 indexNye County26Douglas County: 22 indexDouglas County22
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2025
index		Change on 2024
1Clark County61-3
2Washoe County500
3White Pine County45+1
4Carson City42-3
4Elko County42+19
6Lyon County41-1
7Churchill County40-4
8Nye County26-5
9Douglas County220

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 2025 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), 2025) [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), 2025. 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. 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), 2025. 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.

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), 2025 [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 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_nevada_by_2025,
  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), 2025}},
  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. 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), 2025
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
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/nevada-counties.
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}
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Questions

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

Clark County, with 61 in 2025, according to the U.S. Environmental Protection Agency.

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

Douglas County, with 22 in 2025.

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 2025 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Nevada: more rankings