Annual Air Quality
Los Angeles County

Air Quality Days by Year, 1980 – 2021

Downtown Los Angeles slyline looking northeast. Los Angeles Almanac Photo.

The Air Quality Index Summary Report displays an annual summary of Air Quality Index (AQI) values for all U.S. counties. The AQI is an indicator of overall air quality, taking into account all criteria air pollutants (such as ozone, NO2, PM2.5 and PM10) measured within the county. Although the AQI includes all available pollutant measurements, each of the 11 monitoring stations in Los Angeles County (located in Azusa, Compton, Glendora, Lancaster, LAX, Long Beach, Downtown Los Angeles, Pasadena, Reseda and Santa Clarita), as in all counties, measure some, but not all, of the pollutants.

All years were measured over 365 days, except Leap Years (marked with obelus “†”), measured over 366 days.

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

2021
41
228
70
26
1

2020†
60
169
77
44
16

2019
66
213
57
28
1

2018
35
222
89
18
1

2017
38
207
74
38
8

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

2016†
32
230
81
19
4

2015
26
207
95
36
1

2014
23
234
80
26
2

2013
22
243
75
25
0

2012†
33
203
93
35
2

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

2011
17
227
82
36
3

2010
32
219
99
15
0

2009
34
213
71
43
4

2008†
31
213
68
46
8

2007
45
193
91
30
6

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

2006
64
172
79
39
11

2005
57
170
77
49
12

2004†
29
179
87
67
4

2003
41
154
83
57
30

2002
34
152
104
53
22

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

2001
20
159
127
48
11

2000†
27
164
114
51
10

1999
17
180
140
27
1

1998
54
193
72
22
24

1997
33
171
116
32
13

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

1996†
42
154
91
47
32

1995
43
108
109
45
60

1994
22
124
96
41
82

1993
29
108
111
45
72

1992†
22
104
92
59
89

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

1991
16
117
96
51
85

1990
17
118
84
57
89

1989
10
69
110
63
113

1988†
9
65
84
63
145

1987
6
91
87
52
129

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

1986
7
72
92
54
140

1985
10
82
91
43
139

1984†
5
71
101
52
137

1983
11
102
80
37
135

1982
8
83
91
54
129

Year
Good Quality Air Days
Moderate Quality Air Days
Unhealthy Air for Sensitive Groups
Unhealthy Air Days
Very Unhealthy or Hazardous Air Days

1981
4
56
99
46
160

1980†
6
74
80
47
159

* Non-final statistics. Preliminary until May of following year.

† Leap year with 366 days.

Source: Air Quality Index Report, U.S. Environmental Protection Agency