Counties in Nevada by share of days with good air quality (US EPA AQI)

Nye County had the highest share of days with good air quality (US EPA AQI) of 9 counties in 2017, at 94.8%. Clark County had the lowest, at 27.4%. The median was 80.9%. Source: EPA.

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Highest94.8Nye County
Lowest27.4Clark County
Median80.99 counties

Map of counties, 2017

Churchill County: 80.9 %Clark County: 27.4 %Douglas County: 80.8 %Elko County: 91.4 %Lyon County: 84.6 %Nye County: 94.8 %Washoe County: 45.2 %White Pine County: 81.2 %Carson City: 69.3 %
  • Under 60
  • 60 to 81
  • 81 to 87
  • 87 and over
  • No data
%, 2017. 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, 2017

Nye County: 94.8 %Nye County94.8Elko County: 91.4 %Elko County91.4Lyon County: 84.6 %Lyon County84.6White Pine County: 81.2 %White Pine County81.2Churchill County: 80.9 %Churchill County80.9Douglas County: 80.8 %Douglas County80.8Carson City: 69.3 %Carson City69.3Washoe County: 45.2 %Washoe County45.2Clark County: 27.4 %Clark County27.4Nye County: 94.8 %Nye County94.8Elko County: 91.4 %Elko County91.4Lyon County: 84.6 %Lyon County84.6White Pine County: 81.2 %White Pine County81.2Churchill County: 80.9 %Churchill County80.9Douglas County: 80.8 %Douglas County80.8Carson City: 69.3 %Carson City69.3Washoe County: 45.2 %Washoe County45.2Clark County: 27.4 %Clark County27.4
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Nye County94.8-0.6 pts
2Elko County91.4-7.2 pts
3Lyon County84.6+4.5 pts
4White Pine County81.2-1.9 pts
5Churchill County80.90 pts
6Douglas County80.8+1 pts
7Carson City69.3-7.7 pts
8Washoe County45.2-10.3 pts
9Clark County27.4+5.8 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) 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; both counts are stored with each value.

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 2017 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: good days 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: good days as a share of days with an AQI, calculated with stored counts (Counties in Nevada by share of days with good air quality (US EPA AQI), 2017) [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: good days as a share of days with an AQI, calculated with stored counts, Counties in Nevada by share of days with good air quality (US EPA AQI), 2017. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/nevada-counties?period=2017. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in Nevada by share of days with good air quality (US EPA AQI), 2017. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/nevada-counties?period=2017.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Nevada by share of days with good air quality (US EPA AQI), 2017 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/nevada-counties?period=2017 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_nevada_by_2017,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Nevada by share of days with good air quality (US EPA AQI), 2017}},
  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/good-air-quality-days-share/nevada-counties?period=2017. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days 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: good days as a share of days with an AQI, calculated with stored counts: Counties in Nevada by share of days with good air quality (US EPA AQI), 2017
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/good-air-quality-days-share/nevada-counties?period=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/nevada-counties?period=2017.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days 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 Nevada by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Nye County, with 94.8% in 2017, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Clark County, with 27.4% in 2017.

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: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 3 counties have no value for 2017 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in Nevada: more rankings