Air Monitoring Data

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This page provides access to current and historical air quality and meteorological information based on measurements taken at stations in the Air District’s air monitoring network. Some of the data on these pages is raw or unchecked data that may contain errors.

Measurement: PM2.5

PM2.5 is a term for fine particulate matter pollution.  PM2.5 is primarily a problem in the wintertime in the Bay Area, when wood burning constitutes the major source.

Daily AQI Measurements

Each cell in this chart shows the estimated hourly Air Quality Index (AQI) values for PM2.5.  

As established by the U.S. EPA, the AQI for PM2.5 is based on 24-hour concentrations, so hourly readings are only estimates.  

The column at far right shows the preliminary AQI value for the day, based on the 24-hour average concentration.

If the number in the far right column is greater than 100, it means that PM2.5 levels were over the federal health standard.  Values between 101 and 150 in the far right column mean that air quality was in the Unhealthy for Sensitive Groups category for the day.  If the value in the far right column is greater than 150, that means air quality was in the Unhealthy category.

* At this time, PM2.5 measurements at the Napa Valley College location are for informational purposes only.

AQI Key 
Northern Zone
Stations Friday, September 21, 2018
Hourly PST 01234567891011121314151617181920212223
Napa - Napa Valley College
61
55
54
53
51
44
32
39
45
55
55
57
56
53
52
51
56
58
58
San Rafael
45
Sebastopol
46
38
33
27
32
35
40
41
35
30
32
24
29
27
32
29
29
29
27
Vallejo
52
54
54
54
57
56
56
59
57
57
59
58
57
58
57
54
57
54
52
Coast & Central Bay
Stations Friday, September 21, 2018
Hourly PST 01234567891011121314151617181920212223
Berkeley Aquatic Park
49
55
53
50
48
52
58
59
55
51
54
56
58
60
61
58
51
Laney College
59
58
57
56
55
54
54
59
59
63
68
68
67
63
57
59
59
59
56
Oakland East
54
47
42
157
107
85
83
73
71
67
67
60
59
57
55
55
55
53
56
Oakland West
72
71
66
66
63
70
60
70
65
65
68
55
53
52
59
64
74
60
58
San Francisco - Arkansas St.
82
74
71
70
65
62
75
74
70
77
67
54
43
61
52
56
58
58
56
San Pablo - Rumrill
59
59
59
52
51
52
59
59
59
63
62
64
63
60
60
56
58
57
Eastern Zone
Stations Friday, September 21, 2018
Hourly PST 01234567891011121314151617181920212223
Concord
29
31
32
33
31
36
39
38
40
41
41
40
43
51
42
32
24
31
34
Livermore - Rincon Ave.
34
27
26
32
37
41
44
42
40
35
34
40
39
36
38
131
89
70
60
Pleasanton - Owens Ct
55
54
58
58
58
57
59
62
62
52
55
60
56
55
55
54
58
53
58
South Central Bay
Stations Friday, September 21, 2018
Hourly PST 01234567891011121314151617181920212223
Redwood City
44
41
33
20
15
20
27
55
55
75
72
68
67
67
60
55
51
42
44
Santa Clara Valley
Stations Friday, September 21, 2018
Hourly PST 01234567891011121314151617181920212223
Gilroy
27
30
21
15
16
22
38
57
60
63
59
San Jose - Jackson St.
58
58
57
58
56
55
56
57
55
54
56
62
66
64
60
58
66
62
San Jose - Knox Av
57
58
54
57
48
51
54
51
49
43
36
28
41
50
50
46
42
48
56
Spare the Air Status
Spare the Air Status
  • Friday,
    9/21

    No Spare the Air Alert in Effect

  • Saturday,
    9/22

    No Spare the Air Alert in Effect

9/10/2018