Daily Air Quality Index summaries from EPA monitors in Benton, Washington, 1985–2025.
80%
Good days in 2025
36
Median daily AQI, 2025
2
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 Benton, Washington on 365 days. 293 of those days (80%) were in the Good range, and the median daily AQI was 36. That median is higher than the typical monitored county in Washington (median 28 across 30 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 217 days. Across the years with fuller monitoring, the share of Good days fell: an average of 90% in 1986–1988 versus 78% in 2023–2025.
Years with fewer than 120 monitored days (1985) 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
Fine particles (PM2.5)
217
59%
Ozone
99
27%
Coarse particles (PM10)
49
13%
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
293
70
2
0
0
0
36
57
113
PM2.5
2024
366
299
64
3
0
0
0
34
59
126
PM2.5
2023
365
262
99
1
1
2
0
41
61
261
PM2.5
2022
365
278
84
2
1
0
0
38
62
151
PM2.5
2021
365
283
73
6
3
0
0
36
63
180
PM2.5
2020
365
284
69
3
3
1
5
35
58
954
PM2.5
2019
364
273
91
0
0
0
0
39
59
80
PM2.5
2018
365
275
76
12
2
0
0
36
67
188
PM2.5
2017
365
242
109
9
4
1
0
39
73
204
PM2.5
2016
366
307
57
2
0
0
0
35
55
122
PM2.5
2015
362
269
83
8
1
0
1
37
66
483
PM2.5
2014
348
295
52
1
0
0
0
26
54
131
PM2.5
2013
362
279
80
2
0
0
1
29
61
517
PM2.5
2012
364
286
78
0
0
0
0
29
57
99
PM2.5
2011
363
306
56
1
0
0
0
27
57
102
PM2.5
2010
365
314
51
0
0
0
0
27
54
78
PM2.5
2009
362
285
76
0
1
0
0
32
56
168
PM2.5
2008
366
264
102
0
0
0
0
36
62
84
PM2.5
2007
365
287
77
1
0
0
0
28
61
119
PM2.5
2006
365
258
104
3
0
0
0
37
66
149
PM2.5
2005
359
262
94
1
1
0
1
37
61
484
PM2.5
2004
357
260
94
1
1
0
1
37
59
428
PM2.5
2003
353
290
59
3
0
0
1
28
55
1427
PM2.5
2002
358
296
60
2
0
0
0
27
55
116
PM2.5
2001
344
276
64
1
3
0
0
28
56
197
PM2.5
2000
336
284
48
4
0
0
0
19
61
138
PM10
1999
322
290
30
1
1
0
0
18
50
176
PM10
1998
270
262
8
0
0
0
0
14
28
85
PM10
1997
313
309
3
1
0
0
0
16
31
106
PM10
1996
325
319
6
0
0
0
0
16
35
65
PM10
1995
313
310
3
0
0
0
0
14
31
78
PM10
1994
315
304
11
0
0
0
0
18
38
86
PM10
1993
326
306
18
1
0
0
1
21
44
1125
PM10
1992
325
315
8
1
0
0
1
19
35
491
PM10
1991
281
254
20
3
2
0
2
22
50
1706
PM10
1990
155
137
11
3
2
1
1
24
58
329
PM10
1989
166
157
7
1
1
0
0
21
46
163
PM10
1988
154
130
23
1
0
0
0
27
54
129
PM10
1987
156
144
12
0
0
0
0
22
43
64
PM10
1986
171
157
13
1
0
0
0
21
43
104
PM10
1985
37
30
7
0
0
0
0
27
70
85
PM10
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
