Daily Air Quality Index summaries from EPA monitors in Fresno, California, 1980–2025.
29%
Good days in 2025
61
Median daily AQI, 2025
34
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 Fresno, California on 365 days. 105 of those days (29%) were in the Good range, and the median daily AQI was 61. That median is higher than the typical monitored county in California (median 45.5 across 46 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 204 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 24% in 1980–1982 versus 25% in 2023–2025.
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
204
56%
Fine particles (PM2.5)
151
41%
Coarse particles (PM10)
10
3%
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
105
226
31
3
0
0
61
100
164
Ozone
2024
366
71
216
65
14
0
0
67
126
169
Ozone
2023
365
97
210
55
3
0
0
64
112
156
Ozone
2022
365
78
217
67
3
0
0
71
115
159
Ozone
2021
365
62
221
63
17
2
0
68
130
278
PM2.5
2020
366
75
192
59
31
8
1
76
154
346
PM2.5
2019
365
113
186
64
2
0
0
63
115
187
Ozone
2018
365
61
206
79
19
0
0
75
133
185
Ozone
2017
365
76
169
93
26
1
0
75
140
207
Ozone
2016
366
62
199
80
25
0
0
76
140
190
Ozone
2015
365
38
225
78
23
1
0
80
136
205
Ozone
2014
365
48
193
91
33
0
0
83
148
197
Ozone
2013
365
35
191
114
25
0
0
88
147
197
Ozone
2012
366
45
187
92
41
1
0
82
151
212
Ozone
2011
365
26
216
83
40
0
0
80
152
197
PM2.5
2010
365
48
230
65
21
1
0
71
130
209
PM2.5
2009
365
86
163
80
36
0
0
80
150
200
Ozone
2008
366
25
207
92
35
7
0
85
154
228
PM2.5
2007
365
3
213
106
43
0
0
88
153
192
PM2.5
2006
365
59
172
85
47
2
0
82
156
208
Ozone
2005
365
83
167
70
43
2
0
74
154
206
Ozone
2004
366
49
185
107
25
0
0
87
143
195
Ozone
2003
365
32
139
95
87
12
0
107
177
212
Ozone
2002
365
26
106
116
95
22
0
126
190
228
Ozone
2001
365
15
125
113
91
21
0
119
190
263
Ozone
2000
366
47
124
89
87
19
0
112
185
235
Ozone
1999
365
52
113
88
101
11
0
108
185
219
Ozone
1998
365
138
113
43
45
26
0
64
187
230
Ozone
1997
365
115
111
67
58
14
0
71
179
223
Ozone
1996
366
152
79
61
59
15
0
61
177
219
Ozone
1995
365
136
108
59
48
14
0
68
172
222
Ozone
1994
365
133
127
56
45
4
0
64
161
206
Ozone
1993
365
126
119
65
44
11
0
68
164
217
Ozone
1992
366
130
112
59
53
12
0
68
172
217
Ozone
1991
365
91
142
55
53
24
0
79
182
226
Ozone
1990
365
74
153
83
50
5
0
84
164
213
Ozone
1989
365
64
125
91
76
9
0
100
174
217
Ozone
1988
366
68
118
69
78
33
0
100
195
221
Ozone
1987
365
65
121
79
62
38
0
95
201
247
Ozone
1986
365
83
112
77
60
33
0
93
195
232
Ozone
1985
365
56
136
91
61
21
0
100
179
227
Ozone
1984
366
82
134
57
66
27
0
87
190
219
Ozone
1983
365
131
122
57
47
8
0
61
164
218
Ozone
1982
365
98
133
70
49
15
0
77
174
223
Ozone
1981
365
92
131
70
48
24
0
79
182
222
Ozone
1980
366
71
128
77
51
39
0
90
201
238
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 California with a similar median AQI in 2025
