Daily Air Quality Index summaries from EPA monitors in Deschutes, Oregon, 1983–2025.
89%
Good days in 2025
23
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 Deschutes, Oregon on 365 days. 326 of those days (89%) were in the Good range, and the median daily AQI was 23. That median is lower than the typical monitored county in Oregon (median 29 across 21 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 365 days. Across the years with fuller monitoring, the share of Good days rose: an average of 61% in 1988–1990 versus 78% in 2023–2025.
Years with fewer than 120 monitored days (1983, 1984, 1985, 1986, 1987) 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)
365
100%
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
326
36
2
1
0
0
23
52
153
PM2.5
2024
366
258
89
12
7
0
0
39
78
176
PM2.5
2023
365
273
66
10
9
6
1
28
74
413
PM2.5
2022
365
282
77
2
3
1
0
23
62
205
PM2.5
2021
365
298
47
10
7
2
1
25
61
403
PM2.5
2020
366
298
54
4
2
1
7
23
61
1099
PM2.5
2019
365
309
51
4
1
0
0
26
53
154
PM2.5
2018
363
273
76
9
4
1
0
27
66
205
PM2.5
2017
365
280
57
2
15
8
3
27
83
479
PM2.5
2016
327
301
26
0
0
0
0
29
49
65
PM2.5
2015
365
295
64
5
1
0
0
37
61
163
PM2.5
2014
365
299
65
1
0
0
0
37
56
113
PM2.5
2013
365
276
89
0
0
0
0
39
59
86
PM2.5
2012
366
281
67
1
10
3
4
39
64
988
PM2.5
2011
365
294
67
3
1
0
0
36
57
176
PM2.5
2010
365
328
37
0
0
0
0
34
51
86
PM2.5
2009
363
307
55
1
0
0
0
35
54
108
PM2.5
2008
366
307
57
2
0
0
0
24
55
111
PM2.5
2007
362
316
46
0
0
0
0
23
53
81
PM2.5
2006
362
300
62
0
0
0
0
27
57
88
PM2.5
2005
365
294
71
0
0
0
0
26
57
91
PM2.5
2004
353
291
62
0
0
0
0
27
55
79
PM2.5
2003
225
201
24
0
0
0
0
19
52
88
CO
2002
355
262
93
0
0
0
0
32
61
92
PM2.5
2001
348
277
68
1
2
0
0
32
58
178
PM2.5
2000
356
260
94
2
0
0
0
32
61
111
PM2.5
1999
227
154
73
0
0
0
0
38
64
84
PM2.5
1998
212
207
5
0
0
0
0
28
42
66
CO
1997
213
188
25
0
0
0
0
33
52
68
CO
1996
218
193
24
1
0
0
0
28
52
101
PM10
1995
214
187
27
0
0
0
0
30
53
77
PM10
1994
211
177
34
0
0
0
0
32
54
96
PM10
1993
210
138
72
0
0
0
0
44
63
94
CO
1992
218
160
58
0
0
0
0
42
59
93
CO
1991
213
141
72
0
0
0
0
43
64
91
CO
1990
218
147
71
0
0
0
0
41
62
81
CO
1989
214
131
83
0
0
0
0
41
69
95
CO
1988
247
137
110
0
0
0
0
48
70
100
CO
1987
60
53
7
0
0
0
0
28
60
81
PM10
1986
61
55
6
0
0
0
0
27
49
92
PM10
1985
61
48
12
1
0
0
0
24
60
121
PM10
1984
58
50
8
0
0
0
0
27
53
84
PM10
1983
36
32
4
0
0
0
0
23
51
60
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 Oregon with a similar median AQI in 2025
