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Air Monitoring Data

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.

How to Use the Air Monitoring Data Page

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.  

At the end of the day, a column at far right will show the preliminary AQI value for the day, based on the 24-hour average concentration.

If the number in the far right column at the end of the day 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.

AQI Key
Northern Zone
Stations Tuesday, March 03, 2015
Hourly PST 01234567891011121314151617181920212223
Napa
58
49
45
53
56
55
57
58
51
42
44
45
39
45
45
45
50
46
San Rafael
48
45
39
38
36
35
32
43
51
54
56
53
64
60
54
44
45
48
Sebastopol
57
52
49
43
45
39
36
32
27
22
30
36
35
32
26
22
17
17
Vallejo
55
54
47
40
41
37
46
50
52
47
40
43
37
35
32
35
30
25
Coast & Central Bay
Stations Tuesday, March 03, 2015
Hourly PST 01234567891011121314151617181920212223
Laney College Fwy
36
35
32
30
32
34
34
34
39
60
62
59
56
49
39
52
41
39
Oakland East
14
15
18
18
19
16
16
22
28
50
56
58
66
72
59
52
43
54
Oakland West
55
55
54
53
53
56
60
59
64
60
55
58
54
44
51
53
53
44
San Francisco - Arkansas St.
31
30
42
40
43
44
41
37
44
40
37
45
38
42
40
35
25
23
San Pablo - Rumrill
18
18
17
15
12
20
25
29
42
38
38
35
32
39
32
28
29
27
Eastern Zone
Stations Tuesday, March 03, 2015
Hourly PST 01234567891011121314151617181920212223
Concord
36
35
40
41
45
44
49
41
45
48
53
52
52
54
49
46
42
46
Livermore - Rincon Ave.
27
32
41
42
35
34
32
28
31
32
33
29
25
23
30
33
30
South Central Bay
Stations Tuesday, March 03, 2015
Hourly PST 01234567891011121314151617181920212223
Redwood City
15
10
11
8
0
0
2
3
14
32
49
52
47
40
32
27
24
22
Santa Clara Valley
Stations Tuesday, March 03, 2015
Hourly PST 01234567891011121314151617181920212223
Gilroy
27
30
32
28
29
33
31
30
32
38
51
51
52
47
36
37
35
26
San Jose - Jackson St.
53
44
39
32
26
32
35
32
39
45
47
54
45
37
33
33
40
45
San Jose Fwy
40
45
42
36
26
23
22
28
32
29
29
50
40
26
21
25
40
39
Last Updated: 2/18/2015