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1
YearNumber of Ozone Action Alert DaysNotes:
2
201130
3
201243
These are Ozone Action Day Alerts issued during the traditional summer ozone season,
4
201333
which runs from May 31-August 31
5
201418
6
201525
From 2011-2015, the national ozone standard was 75 parts per billion over an 8-hour average
7
201636
8
201745
From 2016-present, the national ozone standard is 70 parts per billion over an 8-hour average
9
201852
10
201932
Disclaimer: Considering that the national ozone standard was higher prior to 2016, more Ozone Action Day Alerts
11
202043
should be expected from 2016-present assuming similar meteorological conditions and emissions from year to year
12
202165
13
202240
14
202337
15
202452
16
2025
17
18
2024 numbers are up-to-date as of 8/31/24
19
20
SEE THE TABS BELOW FOR A DAY-BY-DAY BREAKDOWN FOR EVERY OZONE SEASON DATING BACK TO 2011
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22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100