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 Saturday, April 20, 2019
Hourly PST 01234567891011121314151617181920212223
Napa - Napa Valley College
12
14
13
11
16
18
20
16
San Rafael
12
10
9
11
14
13
13
10
Sebastopol
25
20
17
19
15
12
10
5
Vallejo
27
22
21
21
23
22
19
16
Coast & Central Bay
Stations Saturday, April 20, 2019
Hourly PST 01234567891011121314151617181920212223
Berkeley Aquatic Park
21
21
27
28
29
29
27
24
27
Laney College
20
18
11
10
11
14
15
16
18
Oakland East
16
8
4
2
0
0
10
15
18
Oakland West
18
17
19
18
19
24
20
15
13
San Francisco - Arkansas St.
11
5
7
8
6
5
5
11
San Pablo - Rumrill
21
19
18
17
21
21
19
16
20
Eastern Zone
Stations Saturday, April 20, 2019
Hourly PST 01234567891011121314151617181920212223
Concord
21
17
19
18
11
20
20
19
20
Livermore - Rincon Ave.
13
12
10
10
13
13
6
55
Pleasanton - Owens Ct
0
0
1
5
7
5
5
11
16
South Central Bay
Stations Saturday, April 20, 2019
Hourly PST 01234567891011121314151617181920212223
Redwood City
0
0
29
14
0
0
28
Santa Clara Valley
Stations Saturday, April 20, 2019
Hourly PST 01234567891011121314151617181920212223
Gilroy
8
8
8
12
12
15
13
7
San Jose - Jackson St.
18
22
27
30
30
27
22
15
San Jose - Knox Av
2
5
11
16
14
13
5
0
Wood Burning Status
Wood Burning Status
  • Saturday,
    4/20

    No Spare the Air Alert in Effect