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 Thursday, November 9, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Napa
15
24
25
29
31
34
32
28
39
39
36
39
45
41
45
46
40
32
29
27
24
31
32
45
36
Napa - Napa Valley College
22
25
23
20
14
22
25
25
25
33
35
37
37
37
42
42
40
30
23
22
28
28
37
30
San Rafael
12
16
19
20
22
22
21
23
35
35
32
37
35
30
32
30
28
30
30
33
33
32
26
26
27
Sebastopol
17
15
24
29
27
24
25
25
27
34
36
35
38
38
31
28
34
32
26
20
16
16
27
27
Vallejo
11
10
15
24
22
26
32
39
42
42
40
41
35
28
35
38
38
29
27
30
40
41
45
40
32
Coast & Central Bay
Stations Thursday, November 9, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Berkeley Aquatic Park
0
14
18
21
23
22
17
17
31
32
27
30
27
28
31
30
36
32
41
35
28
27
27
Laney College
22
22
23
21
24
35
40
43
45
43
47
46
46
46
39
38
45
48
49
51
49
42
38
40
Oakland East
0
0
1
0
4
8
8
6
14
14
15
16
27
24
14
15
20
22
26
32
30
26
23
22
16
Oakland West
5
0
8
12
12
19
15
18
18
18
21
29
29
27
22
32
43
45
41
43
40
33
27
26
25
San Francisco - Arkansas St.
11
8
4
0
0
6
22
27
28
28
10
11
14
13
9
0
12
17
12
21
27
20
37
33
16
San Pablo - Rumrill
9
19
26
27
26
24
37
35
34
34
34
38
33
31
32
33
37
40
40
50
46
42
35
Eastern Zone
Stations Thursday, November 9, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Concord
30
25
21
21
23
22
25
23
30
30
25
25
33
50
33
27
24
27
28
32
35
34
44
45
30
Livermore - Rincon Ave.
0
0
0
0
1
5
5
4
10
10
16
16
8
8
8
10
11
10
18
23
20
16
20
27
11
South Central Bay
Stations Thursday, November 9, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Redwood City
0
0
0
0
31
18
11
20
29
29
27
24
31
34
32
32
31
22
15
16
22
22
7
0
17
Santa Clara Valley
Stations Thursday, November 9, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Gilroy
30
36
22
9
0
0
3
8
8
8
4
0
0
0
2
15
18
5
0
1
0
0
5
17
6
San Jose - Jackson St.
4
4
8
8
2
1
2
1
3
3
16
20
19
18
23
18
9
42
38
31
28
27
20
16
16
San Jose - Knox Av
0
0
2
0
0
0
0
0
9
27
20
22
67
55
37
23
20
22
26
32
35
32
26
21
Wood Burning Status
Wood Burning Status
  • Sunday,
    11/19

    No Spare the Air Alert in Effect

10/17/2017