Daily Air Quality Index summaries from EPA monitors in Johnson, Kansas, 1980–2025.
68%
Good days in 2025
44
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 Johnson, Kansas on 365 days. 250 of those days (68%) were in the Good range, and the median daily AQI was 44. That median is about the same as the typical monitored county in Kansas (median 44 across 11 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 200 days. Across the years with fuller monitoring, the share of Good days rose: an average of 47% in 1980–2002 versus 63% in 2023–2025.
Years with fewer than 120 monitored days (1994, 1995, 1996, 1997, 1999, 2001…) 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)
200
55%
Ozone
162
44%
Coarse particles (PM10)
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
250
112
1
2
0
0
44
60
188
PM2.5
2024
366
257
109
0
0
0
0
44
59
80
Ozone
2023
365
189
166
7
3
0
0
49
70
165
PM2.5
2022
365
227
137
1
0
0
0
44
64
115
PM2.5
2021
364
207
153
4
0
0
0
46
65
138
PM2.5
2020
365
250
114
1
0
0
0
41
61
117
PM2.5
2019
362
308
54
0
0
0
0
38
53
77
Ozone
2018
363
277
86
0
0
0
0
40
61
92
Ozone
2017
364
281
83
0
0
0
0
40
56
100
Ozone
2016
366
315
51
0
0
0
0
37
52
87
Ozone
2015
365
309
56
0
0
0
0
35
54
100
Ozone
2014
365
311
54
0
0
0
0
37
56
84
Ozone
2013
364
286
78
0
0
0
0
40
58
87
Ozone
2012
364
243
100
18
3
0
0
41
86
161
Ozone
2011
364
249
105
9
1
0
0
42
67
161
Ozone
2010
359
266
89
4
0
0
0
41
69
112
Ozone
2009
365
295
69
1
0
0
0
38
57
129
Ozone
2008
365
286
79
0
0
0
0
40
57
100
Ozone
2007
365
267
94
4
0
0
0
39
64
133
Ozone
2006
353
231
117
5
0
0
0
43
77
140
Ozone
2005
360
214
131
15
0
0
0
47
80
150
Ozone
2004
366
272
92
2
0
0
0
42
63
119
Ozone
2003
285
140
115
27
2
1
0
51
101
201
Ozone
2002
122
47
74
1
0
0
0
56
74
114
PM2.5
2001
119
39
79
1
0
0
0
55
74
108
PM2.5
2000
122
47
74
1
0
0
0
54
70
110
PM2.5
1999
118
31
87
0
0
0
0
58
76
89
PM2.5
1997
51
50
1
0
0
0
0
22
34
59
PM10
1996
21
19
2
0
0
0
0
25
50
61
PM10
1995
48
45
3
0
0
0
0
22
43
61
PM10
1994
56
52
4
0
0
0
0
28
45
79
PM10
1993
54
54
0
0
0
0
0
20
31
38
PM10
1992
50
49
1
0
0
0
0
26
35
54
PM10
1991
46
46
0
0
0
0
0
22
39
46
PM10
1990
49
47
2
0
0
0
0
29
44
59
PM10
1989
34
32
2
0
0
0
0
32
44
59
PM10
1981
90
83
6
1
0
0
0
34
47
105
Ozone
1980
348
227
71
40
9
1
0
38
112
203
Ozone
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 Kansas with a similar median AQI in 2025
