Daily Air Quality Index summaries from EPA monitors in Juneau, Alaska, 1986–2025.
84%
Good days in 2025
23
Median daily AQI, 2025
1
Days above 100 in 2025
363
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Juneau, Alaska on 363 days. 306 of those days (84%) were in the Good range, and the median daily AQI was 23. That median is lower than the typical monitored county in Alaska (median 26 across 5 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 363 days. Across the years with fuller monitoring, the share of Good days fell: an average of 94% in 1986–1988 versus 85% in 2023–2025.
Years with fewer than 120 monitored days (1998, 2003, 2005, 2006) 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)
363
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
363
306
56
1
0
0
0
23
58
138
PM2.5
2024
356
304
52
0
0
0
0
24
55
84
PM2.5
2023
364
314
50
0
0
0
0
24
54
78
PM2.5
2022
342
291
51
0
0
0
0
21
56
95
PM2.5
2021
357
315
42
0
0
0
0
20
53
89
PM2.5
2020
361
320
40
1
0
0
0
19
52
101
PM2.5
2019
362
280
79
3
0
0
0
27
60
145
PM2.5
2018
352
268
84
0
0
0
0
31
59
85
PM2.5
2017
356
281
74
1
0
0
0
20
59
103
PM2.5
2016
305
224
81
0
0
0
0
27
63
90
PM2.5
2015
351
262
89
0
0
0
0
28
61
92
PM2.5
2014
351
251
99
1
0
0
0
31
65
124
PM2.5
2013
345
280
63
2
0
0
0
25
58
107
PM2.5
2012
362
277
84
1
0
0
0
28
57
117
PM2.5
2011
353
253
100
0
0
0
0
31
62
89
PM2.5
2010
359
231
127
1
0
0
0
35
70
112
PM2.5
2009
303
229
72
2
0
0
0
29
63
106
PM2.5
2008
278
218
58
2
0
0
0
23
63
114
PM2.5
2007
135
106
26
3
0
0
0
22
60
127
PM2.5
2006
108
81
25
2
0
0
0
29
71
133
PM2.5
2005
115
88
25
2
0
0
0
26
62
125
PM2.5
2004
122
95
27
0
0
0
0
29
57
90
PM2.5
2003
82
69
13
0
0
0
0
26
58
88
PM2.5
2002
122
104
18
0
0
0
0
26
59
94
PM2.5
2001
130
107
23
0
0
0
0
23
57
96
PM2.5
2000
126
94
31
1
0
0
0
24
64
107
PM2.5
1999
120
115
5
0
0
0
0
11
39
85
PM2.5
1998
75
75
0
0
0
0
0
9
24
44
PM10
1997
243
240
3
0
0
0
0
9
26
70
PM10
1996
361
331
30
0
0
0
0
12
47
66
PM10
1995
363
345
18
0
0
0
0
13
37
69
PM10
1994
364
346
18
0
0
0
0
14
39
72
PM10
1993
360
306
51
2
1
0
0
17
57
180
PM10
1992
363
323
35
3
0
0
2
14
52
480
PM10
1991
360
289
54
13
2
0
2
19
70
882
PM10
1990
361
302
48
10
1
0
0
21
63
152
PM10
1989
362
308
54
0
0
0
0
22
55
81
PM10
1988
354
334
19
1
0
0
0
13
42
104
PM10
1987
359
342
17
0
0
0
0
13
39
73
PM10
1986
278
258
18
2
0
0
0
18
45
143
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 Alaska with a similar median AQI in 2025
