Daily Air Quality Index summaries from EPA monitors in Schoolcraft, Michigan, 1999–2025.
83%
Good days in 2025
33
Median daily AQI, 2025
5
Days above 100 in 2025
355
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Schoolcraft, Michigan on 355 days. 296 of those days (83%) were in the Good range, and the median daily AQI was 33. That median is lower than the typical monitored county in Michigan (median 39 across 26 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 206 days. Across the years with fuller monitoring, the share of Good days rose: an average of 82% in 2001–2003 versus 85% in 2023–2025.
Years with fewer than 120 monitored days (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)
206
58%
Ozone
149
42%
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
355
296
54
3
2
0
0
33
64
167
PM2.5
2024
360
317
43
0
0
0
0
33
52
93
PM2.5
2023
360
298
59
3
0
0
0
36
61
134
Ozone
2022
362
318
43
1
0
0
0
35
55
126
PM2.5
2021
360
269
88
3
0
0
0
37
58
112
PM2.5
2020
347
323
21
3
0
0
0
34
48
133
Ozone
2019
364
339
25
0
0
0
0
31
46
90
Ozone
2018
351
309
40
2
0
0
0
33
52
105
Ozone
2017
358
324
33
1
0
0
0
33
50
101
PM2.5
2016
350
310
31
9
0
0
0
32
51
147
PM2.5
2015
364
311
50
3
0
0
0
35
54
133
PM2.5
2014
364
304
57
3
0
0
0
34
56
121
PM2.5
2013
244
213
28
3
0
0
0
35
54
126
Ozone
2012
234
195
25
11
3
0
0
35
71
169
Ozone
2011
240
209
29
2
0
0
0
35
54
126
Ozone
2010
244
204
34
5
1
0
0
33
61
164
Ozone
2009
244
222
21
1
0
0
0
31
50
140
Ozone
2008
240
205
35
0
0
0
0
32
56
100
Ozone
2007
238
190
30
16
2
0
0
35
77
166
Ozone
2006
297
259
32
4
2
0
0
36
56
185
Ozone
2005
365
308
42
12
3
0
0
34
67
182
Ozone
2004
362
331
25
6
0
0
0
36
49
136
Ozone
2003
358
302
47
7
1
1
0
37
58
214
Ozone
2002
361
297
53
8
3
0
0
33
61
164
Ozone
2001
156
122
34
0
0
0
0
22
60
82
PM2.5
2000
97
80
17
0
0
0
0
17
55
69
PM2.5
1999
9
7
2
0
0
0
0
17
61
61
PM2.5
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 Michigan with a similar median AQI in 2025
