Daily Air Quality Index summaries from EPA monitors in Stevens, Washington, 1992–2025.
69%
Good days in 2025
35
Median daily AQI, 2025
9
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 Stevens, Washington on 365 days. 252 of those days (69%) were in the Good range, and the median daily AQI was 35. 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 341 days. Across the years with fuller monitoring, the share of Good days rose: an average of 55% in 2001–2003 versus 65% in 2023–2025.
Years with fewer than 120 monitored days (1992, 1996, 1997, 1998, 1999, 2000) 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)
341
93%
Coarse particles (PM10)
24
7%
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
252
104
3
4
2
0
35
63
243
PM2.5
2024
366
257
109
0
0
0
0
34
61
98
PM2.5
2023
365
204
153
4
2
2
0
46
70
271
PM2.5
2022
365
208
149
7
1
0
0
43
72
153
PM2.5
2021
365
203
146
6
8
2
0
44
74
223
PM2.5
2020
366
219
138
1
2
2
4
42
66
957
PM2.5
2019
365
223
141
1
0
0
0
36
67
146
PM2.5
2018
365
200
148
8
8
1
0
46
73
220
PM2.5
2017
365
195
153
8
8
1
0
47
74
201
PM2.5
2016
366
254
110
2
0
0
0
34
65
110
PM2.5
2015
362
224
126
10
2
0
0
36
73
161
PM2.5
2014
365
223
138
3
1
0
0
39
67
155
PM2.5
2013
365
215
149
1
0
0
0
42
69
101
PM2.5
2012
366
216
150
0
0
0
0
43
65
88
PM2.5
2011
363
226
136
1
0
0
0
34
71
107
PM2.5
2010
365
223
142
0
0
0
0
41
70
89
PM2.5
2009
365
217
148
0
0
0
0
42
69
90
PM2.5
2008
366
186
171
8
1
0
0
49
75
156
PM2.5
2007
365
193
172
0
0
0
0
47
67
95
PM2.5
2006
355
186
167
2
0
0
0
47
73
114
PM2.5
2005
365
205
158
2
0
0
0
42
78
106
PM2.5
2004
366
180
186
0
0
0
0
51
70
96
PM2.5
2003
365
199
165
1
0
0
0
47
70
105
PM2.5
2002
178
64
113
1
0
0
0
57
82
111
PM2.5
2001
121
90
30
0
1
0
0
33
69
151
PM10
2000
108
99
8
0
1
0
0
23
46
155
PM10
1999
101
98
2
1
0
0
0
22
41
126
PM10
1998
56
52
3
1
0
0
0
24
45
117
PM10
1997
52
34
17
0
1
0
0
39
76
176
PM10
1996
5
4
0
1
0
0
0
28
141
141
PM10
1992
23
8
15
0
0
0
0
61
79
95
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
