Daily Air Quality Index summaries from EPA monitors in Yakima, Washington, 1980–2025.
62%
Good days in 2025
41
Median daily AQI, 2025
3
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Yakima, Washington on 365 days. 226 of those days (62%) were in the Good range, and the median daily AQI was 41. That median is higher than the typical monitored county in Washington (median 28 across 30 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 364 days. Across the years with fuller monitoring, the share of Good days fell: an average of 87% in 1980–1982 versus 62% in 2023–2025.
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
Fine particles (PM2.5)
364
100%
Coarse particles (PM10)
1
<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
365
226
136
2
1
0
0
41
68
154
PM2.5
2024
366
248
111
6
1
0
0
37
63
153
PM2.5
2023
365
203
158
1
1
2
0
46
69
233
PM2.5
2022
365
178
181
5
1
0
0
51
82
158
PM2.5
2021
365
175
163
12
14
1
0
52
90
210
PM2.5
2020
366
198
153
6
2
3
4
46
79
743
PM2.5
2019
365
178
177
10
0
0
0
51
79
127
PM2.5
2018
365
173
176
7
7
2
0
52
82
239
PM2.5
2017
365
193
143
21
5
1
2
48
95
317
PM2.5
2016
366
211
143
8
4
0
0
44
74
199
PM2.5
2015
363
190
153
16
4
0
0
48
87
192
PM2.5
2014
365
227
129
7
2
0
0
39
70
158
PM2.5
2013
365
174
173
14
4
0
0
52
82
158
PM2.5
2012
366
196
162
3
5
0
0
48
76
177
PM2.5
2011
364
236
118
8
2
0
0
36
76
158
PM2.5
2010
365
244
117
4
0
0
0
34
72
140
PM2.5
2009
365
224
131
9
1
0
0
42
77
153
PM2.5
2008
366
194
157
14
1
0
0
48
77
153
PM2.5
2007
365
182
176
7
0
0
0
51
78
130
PM2.5
2006
365
175
177
11
2
0
0
51
80
160
PM2.5
2005
365
245
106
13
1
0
0
32
78
151
PM2.5
2004
309
219
81
6
3
0
0
29
70
156
PM2.5
2003
246
202
42
2
0
0
0
21
64
122
CO
2002
249
201
46
2
0
0
0
24
65
136
CO
2001
361
313
44
4
0
0
0
18
56
146
CO
2000
366
340
23
3
0
0
0
15
41
124
CO
1999
361
336
24
1
0
0
0
17
43
134
CO
1998
365
353
12
0
0
0
0
19
39
75
CO
1997
297
259
38
0
0
0
0
28
53
100
CO
1996
366
305
60
1
0
0
0
31
58
150
CO
1995
365
322
43
0
0
0
0
31
52
77
CO
1994
363
304
59
0
0
0
0
33
55
100
CO
1993
362
274
88
0
0
0
0
39
58
97
CO
1992
359
246
112
1
0
0
0
41
62
103
CO
1991
363
246
110
6
1
0
0
40
74
151
CO
1990
357
248
109
0
0
0
0
41
64
89
CO
1989
351
217
134
0
0
0
0
43
72
98
CO
1988
366
167
198
1
0
0
0
52
76
111
CO
1987
365
158
199
6
1
1
0
54
86
215
CO
1986
365
198
161
4
2
0
0
49
76
170
CO
1985
352
314
28
8
2
0
0
22
52
171
CO
1984
333
252
76
3
1
1
0
27
73
205
CO
1983
225
142
81
2
0
0
0
41
79
118
CO
1982
356
312
42
1
1
0
0
24
55
151
CO
1981
352
298
51
3
0
0
0
22
58
118
CO
1980
291
256
33
2
0
0
0
27
52
108
CO
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 Washington with a similar median AQI in 2025
