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, January 18, 2018
Hourly PST 01234567891011121314151617181920212223
Napa
74
78
78
77
Napa - Napa Valley College
65
65
64
San Rafael
74
71
74
79
Sebastopol
79
69
63
64
Vallejo
73
77
74
79
Coast & Central Bay
Stations Thursday, January 18, 2018
Hourly PST 01234567891011121314151617181920212223
Berkeley Aquatic Park
97
99
90
Laney College
84
87
97
93
Oakland East
69
74
76
74
Oakland West
87
101
123
103
San Francisco - Arkansas St.
112
102
107
101
San Pablo - Rumrill
77
83
90
Eastern Zone
Stations Thursday, January 18, 2018
Hourly PST 01234567891011121314151617181920212223
Concord
48
42
51
51
Livermore - Rincon Ave.
59
54
61
57
South Central Bay
Stations Thursday, January 18, 2018
Hourly PST 01234567891011121314151617181920212223
Redwood City
82
73
76
79
Santa Clara Valley
Stations Thursday, January 18, 2018
Hourly PST 01234567891011121314151617181920212223
Gilroy
51
51
46
62
San Jose - Jackson St.
74
71
67
58
San Jose - Knox Av
86
83
82
77
Wood Burning Status
Wood Burning Status
  • Thursday,
    1/18

    No Spare the Air Alert in Effect

10/17/2017