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 Wednesday, February 20, 2019
Hourly PST 01234567891011121314151617181920212223
Napa - Napa Valley College
15
20
29
29
25
21
15
15
18
18
11
8
6
7
5
5
5
2
5
7
12
16
15
San Rafael
11
5
5
2
0
0
0
0
2
0
0
0
0
4
10
13
19
24
48
47
44
32
20
Sebastopol
8
10
5
0
0
0
0
1
5
8
8
4
2
5
5
2
3
2
1
2
0
0
Vallejo
20
18
11
3
4
10
13
11
10
7
5
7
8
8
4
6
15
16
20
23
20
16
18
Coast & Central Bay
Stations Wednesday, February 20, 2019
Hourly PST 01234567891011121314151617181920212223
Berkeley Aquatic Park
20
18
13
11
10
5
9
12
15
14
23
22
18
9
8
12
17
19
20
18
24
26
28
Laney College
10
9
7
3
6
11
12
12
10
9
11
14
11
10
13
11
10
11
14
15
12
10
Oakland East
26
27
22
15
10
5
9
10
10
5
0
0
0
0
0
5
11
18
22
23
22
17
13
Oakland West
11
3
0
11
12
2
0
0
9
12
8
6
5
7
8
12
17
19
18
15
16
12
4
San Francisco - Arkansas St.
15
18
19
16
10
9
7
8
14
15
12
6
11
20
18
20
22
24
20
16
15
18
San Pablo - Rumrill
27
26
21
15
10
11
16
18
13
13
11
8
10
9
11
14
21
25
27
30
23
24
22
Eastern Zone
Stations Wednesday, February 20, 2019
Hourly PST 01234567891011121314151617181920212223
Concord
14
13
11
10
7
3
2
1
0
0
0
0
0
0
0
0
0
0
2
8
6
3
10
Livermore - Rincon Ave.
12
14
9
7
12
12
4
4
10
13
11
8
6
7
12
12
8
6
11
16
18
20
18
Pleasanton - Owens Ct
10
15
16
16
15
7
12
12
10
9
7
8
6
5
7
8
10
13
17
15
14
9
South Central Bay
Stations Wednesday, February 20, 2019
Hourly PST 01234567891011121314151617181920212223
Redwood City
7
8
8
4
6
15
16
10
15
50
58
51
44
32
22
24
22
18
17
19
12
0
Santa Clara Valley
Stations Wednesday, February 20, 2019
Hourly PST 01234567891011121314151617181920212223
Gilroy
40
24
16
12
2
9
21
25
46
29
23
18
40
18
56
37
22
20
16
14
20
22
San Jose - Jackson St.
33
27
28
25
25
25
23
24
22
20
16
16
21
19
18
17
17
21
21
23
30
34
30
San Jose - Knox Av
38
33
29
25
17
8
10
13
15
14
11
12
6
5
11
10
7
12
20
29
25
21
23
Wood Burning Status
Wood Burning Status
  • Wednesday,
    2/20

    No Spare the Air Alert in Effect

  • Thursday,
    2/21

    No Spare the Air Alert in Effect