Daily Air Quality Index summaries from EPA monitors in Kootenai, Idaho, 1986–2025.
78%
Good days in 2025
31
Median daily AQI, 2025
3
Days above 100 in 2025
352
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Kootenai, Idaho on 352 days. 274 of those days (78%) were in the Good range, and the median daily AQI was 31. That median is lower than the typical monitored county in Idaho (median 35 across 18 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 352 days. Across the years with fuller monitoring, the share of Good days fell: an average of 89% in 1990–1997 versus 79% in 2023–2025.
Years with fewer than 120 monitored days (1991, 1992, 1993, 1995, 1996, 1998…) 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)
352
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
352
274
75
3
0
0
0
31
58
118
PM2.5
2024
355
291
63
1
0
0
0
24
57
109
PM2.5
2023
361
279
78
2
1
1
0
32
60
222
PM2.5
2022
359
264
88
4
3
0
0
29
62
186
PM2.5
2021
357
268
81
3
5
0
0
31
60
195
PM2.5
2020
354
288
58
1
2
4
1
26
55
518
PM2.5
2019
355
281
74
0
0
0
0
31
57
88
PM2.5
2018
331
240
81
5
4
1
0
33
65
229
PM2.5
2017
355
267
77
6
0
5
0
31
63
293
PM2.5
2016
351
285
66
0
0
0
0
29
55
85
PM2.5
2015
324
226
92
3
3
0
0
40
70
172
PM2.5
2011
181
169
12
0
0
0
0
41
49
67
Ozone
2010
180
175
5
0
0
0
0
37
46
84
Ozone
2009
259
212
47
0
0
0
0
40
54
69
Ozone
2008
364
258
105
1
0
0
0
41
62
113
PM2.5
2007
358
238
117
3
0
0
0
43
68
105
PM2.5
2006
365
211
150
4
0
0
0
45
69
132
PM2.5
2005
365
182
182
1
0
0
0
51
70
105
PM2.5
2004
365
176
185
4
0
0
0
51
66
143
PM2.5
2003
364
239
123
2
0
0
0
38
63
111
PM2.5
2002
360
215
142
3
0
0
0
42
69
112
PM2.5
2001
354
304
48
2
0
0
0
21
54
105
PM10
2000
364
314
50
0
0
0
0
23
54
99
PM10
1999
364
339
22
1
2
0
0
20
44
167
PM10
1998
119
114
5
0
0
0
0
20
39
76
PM10
1997
120
110
10
0
0
0
0
23
46
69
PM10
1996
118
103
13
2
0
0
0
25
52
135
PM10
1995
117
108
9
0
0
0
0
26
49
63
PM10
1994
124
108
16
0
0
0
0
31
53
84
PM10
1993
117
94
23
0
0
0
0
32
58
91
PM10
1992
109
90
16
1
1
0
1
29
58
487
PM10
1991
110
76
33
0
0
0
1
33
61
340
PM10
1990
175
154
20
1
0
0
0
28
52
107
PM10
1989
107
92
13
1
0
0
1
30
53
319
PM10
1988
81
60
20
0
1
0
0
30
61
155
PM10
1987
68
47
21
0
0
0
0
34
61
85
PM10
1986
77
60
17
0
0
0
0
34
60
86
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 Idaho with a similar median AQI in 2025
