Wildfire Information

See current air quality conditions and our wildfire safety tips.

Air Monitoring Data

Filters
Filters
Close
  • Displays
    Daily |  Monthly |  Yearly
  • Historical Data
    RadDatePicker
    RadDatePicker
    Open the calendar popup.
  • View
  • Measurement
  • Stations

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 Wednesday, October 11, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Napa
157
221
345
389
326
364
322
261
202
177
156
120
137
142
158
171
197
210
Napa - Napa Valley College
92
78
108
122
121
130
137
182
265
295
310
319
288
241
193
171
154
119
168
197
206
224
284
193
San Rafael
77
80
74
72
73
74
76
75
77
96
105
116
125
135
118
78
64
59
60
59
67
80
97
129
87
Sebastopol
84
78
81
79
77
80
80
85
105
121
99
103
124
116
91
70
66
62
49
45
53
55
60
79
Vallejo
97
91
88
74
70
72
73
81
104
189
333
309
224
185
175
166
155
104
75
62
59
58
56
54
156
Coast & Central Bay
Stations Wednesday, October 11, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Berkeley Aquatic Park
85
79
71
72
67
64
108
152
153
137
137
114
95
75
62
54
55
65
63
79
94
89
Laney College
77
75
78
79
81
79
76
75
146
171
166
148
103
81
64
57
64
63
83
113
99
Oakland East
59
68
68
74
70
70
70
74
98
171
188
185
183
175
156
111
83
72
65
64
65
70
78
123
Oakland West
84
76
73
66
65
73
74
78
75
108
152
152
160
161
145
108
83
66
58
64
65
86
108
96
San Francisco - Arkansas St.
72
71
69
62
64
63
64
65
69
83
97
122
131
112
83
65
58
53
54
56
59
71
84
117
78
San Pablo - Rumrill
77
72
65
57
54
56
64
93
112
138
155
158
156
157
152
106
80
64
63
61
67
82
95
96
Eastern Zone
Stations Wednesday, October 11, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Concord
81
86
91
83
90
84
86
106
116
155
174
210
225
212
219
217
196
189
187
183
176
167
160
153
169
Livermore - Rincon Ave.
87
87
86
80
83
84
78
89
96
112
132
151
151
127
99
98
93
110
91
89
107
113
126
141
106
South Central Bay
Stations Wednesday, October 11, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Redwood City
81
74
69
70
65
74
75
81
85
96
114
160
184
190
184
171
151
108
81
66
59
68
99
118
126
Santa Clara Valley
Stations Wednesday, October 11, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 AQI
Gilroy
59
66
69
71
67
61
54
57
62
68
109
135
145
159
174
190
180
159
115
78
59
54
114
San Jose - Jackson St.
65
62
59
58
49
63
63
66
77
96
112
124
152
166
183
194
173
143
92
69
59
58
58
60
110
San Jose - Knox Av
60
62
64
67
66
65
71
76
75
96
109
118
134
164
173
181
166
134
87
66
56
59
62
66
104
Spare the Air Status
Spare the Air Status
  • Sunday,
    10/22

    No Spare the Air Alert in Effect

  • Monday,
    10/23

    No Spare the Air Alert in Effect

10/17/2017