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.  View AQI flyer.

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.

Refresh this page to view the current day.


AQI Key 
Northern Zone
Stations Friday, January 18, 2019
Hourly PST 01234567891011121314151617181920212223
Napa - Napa Valley College
40
38
29
21
17
19
22
21
23
22
25
30
40
35
27
22
26
25
31
47
51
San Rafael
17
10
8
12
14
9
9
13
25
35
43
38
40
41
41
35
30
32
39
51
52
Sebastopol
77
59
43
34
25
25
21
19
20
14
13
19
26
34
34
33
33
33
46
50
46
Vallejo
54
53
51
42
33
31
32
37
35
38
46
40
41
45
45
42
45
49
46
48
Coast & Central Bay
Stations Friday, January 18, 2019
Hourly PST 01234567891011121314151617181920212223
Berkeley Aquatic Park
54
52
50
50
48
43
35
42
53
57
64
62
62
58
59
57
55
54
56
57
61
Laney College
38
40
40
39
35
27
26
32
43
49
49
43
42
46
46
46
50
51
54
60
Oakland East
37
34
28
25
25
20
17
19
20
27
30
27
28
33
39
38
36
37
33
40
45
Oakland West
57
52
47
38
35
37
33
33
40
45
41
39
42
42
51
48
47
38
44
51
51
San Francisco - Arkansas St.
64
58
58
55
46
54
56
53
56
57
57
52
40
33
27
40
39
40
49
57
62
San Pablo - Rumrill
48
45
43
40
39
34
30
27
49
50
50
52
51
52
56
52
55
53
52
58
60
Eastern Zone
Stations Friday, January 18, 2019
Hourly PST 01234567891011121314151617181920212223
Concord
15
11
14
18
17
17
17
15
18
21
34
29
29
31
26
19
20
25
35
36
37
Livermore - Rincon Ave.
19
22
13
11
12
8
10
13
21
32
32
39
38
30
19
14
15
22
32
41
52
Pleasanton - Owens Ct
27
27
31
30
25
34
38
31
47
38
32
41
37
27
18
11
12
18
24
27
26
South Central Bay
Stations Friday, January 18, 2019
Hourly PST 01234567891011121314151617181920212223
Redwood City
47
46
36
63
31
11
12
53
40
32
31
55
46
40
35
34
30
19
51
56
64
Santa Clara Valley
Stations Friday, January 18, 2019
Hourly PST 01234567891011121314151617181920212223
Gilroy
38
38
38
25
15
10
7
8
12
15
47
46
51
48
43
42
36
26
13
7
14
San Jose - Jackson St.
52
54
53
51
46
32
27
32
35
40
45
45
48
47
36
37
41
38
53
59
66
San Jose - Knox Av
51
46
50
48
47
44
47
47
54
55
53
38
27
24
27
22
19
30
36
37
Wood Burning Status
Wood Burning Status
  • Friday,
    1/18

    No Spare the Air Alert in Effect

  • Saturday,
    1/19

    No Spare the Air Alert in Effect