Daily Air Quality Index summaries from EPA monitors in Burleigh, North Dakota, 1985–2025.
78%
Good days in 2025
39
Median daily AQI, 2025
12
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 Burleigh, North Dakota on 365 days. 285 of those days (78%) were in the Good range, and the median daily AQI was 39. That median is about the same as the typical monitored county in North Dakota (median 38 across 9 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 220 days. Across the years with fuller monitoring, the share of Good days fell: an average of 90% in 1985–2000 versus 71% in 2023–2025.
Years with fewer than 120 monitored days (1994, 1995, 1996, 1997, 1998, 1999…) 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
Ozone
220
60%
Fine particles (PM2.5)
137
38%
Coarse particles (PM10)
5
1%
Nitrogen dioxide (NO₂)
3
1%
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
285
68
8
3
1
0
39
60
218
Ozone
2024
366
268
88
9
1
0
0
39
63
174
Ozone
2023
365
225
118
14
7
1
0
42
81
272
PM2.5
2022
365
260
105
0
0
0
0
39
59
99
PM2.5
2021
365
265
83
12
5
0
0
38
70
183
PM2.5
2020
366
302
64
0
0
0
0
37
55
77
PM2.5
2019
365
299
66
0
0
0
0
36
55
90
PM2.5
2018
365
247
114
2
2
0
0
41
61
153
PM2.5
2017
365
282
80
2
0
1
0
39
57
222
Ozone
2016
337
320
16
1
0
0
0
31
44
117
Ozone
2015
365
301
58
5
1
0
0
37
56
156
Ozone
2014
365
316
48
1
0
0
0
36
52
113
Ozone
2013
365
296
69
0
0
0
0
39
55
84
Ozone
2012
366
283
83
0
0
0
0
40
56
72
Ozone
2011
363
303
60
0
0
0
0
38
53
76
Ozone
2010
362
250
112
0
0
0
0
42
61
90
PM2.5
2009
365
304
61
0
0
0
0
39
55
86
Ozone
2008
366
332
33
1
0
0
0
35
50
115
Ozone
2007
365
334
31
0
0
0
0
32
50
74
Ozone
2006
365
323
41
1
0
0
0
34
51
113
Ozone
2005
181
154
27
0
0
0
0
26
54
76
PM2.5
2004
121
101
20
0
0
0
0
31
53
72
PM2.5
2003
124
93
31
0
0
0
0
40
56
73
PM2.5
2002
120
95
25
0
0
0
0
32
57
68
PM2.5
2001
121
96
25
0
0
0
0
37
59
75
PM2.5
2000
124
96
28
0
0
0
0
36
55
74
PM2.5
1999
93
74
19
0
0
0
0
31
58
80
PM2.5
1998
61
61
0
0
0
0
0
15
24
48
PM10
1997
58
58
0
0
0
0
0
11
20
25
PM10
1996
58
58
0
0
0
0
0
10
17
26
PM10
1995
59
59
0
0
0
0
0
14
28
33
PM10
1994
61
61
0
0
0
0
0
14
24
44
PM10
1993
59
58
1
0
0
0
0
15
27
51
PM10
1992
60
59
1
0
0
0
0
16
28
66
PM10
1991
55
54
1
0
0
0
0
17
31
65
PM10
1990
60
57
3
0
0
0
0
17
38
76
PM10
1989
60
59
1
0
0
0
0
16
34
56
PM10
1988
61
60
1
0
0
0
0
17
29
51
PM10
1987
60
56
4
0
0
0
0
18
41
72
PM10
1986
173
167
6
0
0
0
0
23
39
84
PM10
1985
135
129
6
0
0
0
0
24
40
58
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 North Dakota with a similar median AQI in 2025
