Daily Air Quality Index summaries from EPA monitors in Elko, Nevada, 1988–2025.
86%
Good days in 2025
42
Median daily AQI, 2025
2
Days above 100 in 2025
364
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Elko, Nevada on 364 days. 314 of those days (86%) were in the Good range, and the median daily AQI was 42. That median is about the same as the typical monitored county in Nevada (median 42 across 9 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 182 days. Across the years with fuller monitoring, the share of Good days fell: an average of 93% in 1993–1995 versus 87% in 2023–2025.
Years with fewer than 120 monitored days (1988, 1989, 1990, 1991, 1992, 1997) are shown in the table but left out of comparisons and trend statements.
How the days broke down each year
Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.
Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous
Typical and high-end AQI over time
The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.
Median daily AQI
90th-percentile daily AQI
Main pollutant by day, 2025
On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.
Pollutant
Days as main pollutant
Share of monitored days
Ozone
182
50%
Coarse particles (PM10)
177
49%
Fine particles (PM2.5)
5
1%
Year-by-year data
Annual AQI summary by year
Year
Days with AQI
Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous
Median AQI
90th pct.
Max AQI
Main pollutant
2025
364
314
48
1
1
0
0
42
54
160
Ozone
2024
365
318
46
1
0
0
0
23
51
113
PM10
2023
364
318
46
0
0
0
0
31
51
74
PM10
2022
365
321
42
2
0
0
0
38
51
149
PM10
2021
365
282
73
9
1
0
0
42
71
156
Ozone
2020
363
304
55
1
3
0
0
30
57
169
PM10
2019
365
356
9
0
0
0
0
14
31
77
PM10
2018
346
296
46
4
0
0
0
19
61
126
PM10
2017
361
330
30
0
1
0
0
24
49
164
PM10
2016
345
340
4
1
0
0
0
20
33
134
PM10
2015
359
314
45
0
0
0
0
30
54
97
PM10
2014
357
327
29
1
0
0
0
32
49
123
PM10
2013
361
351
10
0
0
0
0
20
38
83
PM10
2012
359
328
31
0
0
0
0
23
48
90
PM10
2011
326
313
13
0
0
0
0
19
41
85
PM10
2010
300
294
5
1
0
0
0
20
38
139
PM10
2009
319
307
11
1
0
0
0
20
42
106
PM10
2008
178
173
5
0
0
0
0
13
33
61
PM10
2007
305
282
23
0
0
0
0
24
45
82
PM10
2006
333
313
20
0
0
0
0
21
45
90
PM10
2005
260
252
8
0
0
0
0
18
35
67
PM10
2004
359
352
7
0
0
0
0
18
33
62
PM10
2003
353
349
3
1
0
0
0
16
33
104
PM10
2002
322
310
11
1
0
0
0
19
32
130
PM10
2001
290
279
11
0
0
0
0
19
39
74
PM10
2000
243
232
11
0
0
0
0
17
43
66
PM10
1999
353
340
13
0
0
0
0
21
41
90
PM10
1998
136
133
3
0
0
0
0
14
36
75
PM2.5
1997
114
114
0
0
0
0
0
19
34
45
PM2.5
1996
123
109
14
0
0
0
0
19
52
83
PM2.5
1995
132
121
11
0
0
0
0
16
44
61
PM2.5
1994
134
121
13
0
0
0
0
21
50
67
PM2.5
1993
126
123
3
0
0
0
0
20
34
63
PM2.5
1992
95
91
4
0
0
0
0
14
33
71
PM2.5
1991
86
86
0
0
0
0
0
14
29
41
PM2.5
1990
73
68
5
0
0
0
0
16
46
68
PM2.5
1989
78
76
2
0
0
0
0
14
32
58
PM2.5
1988
78
77
1
0
0
0
0
17
34
52
PM2.5
What this data can and can’t tell you
It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.
It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.
Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.
Counties in Nevada with a similar median AQI in 2025
