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See current air quality conditions and our wildfire safety tips.

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

Units: micrograms per cubic meter (µg/m3)

PM2.5 is a term for fine particulate matter pollution.  

The federal health standard for PM2.5 is 35 micrograms per cubic meter averaged over a 24-hour day. Any daily 24-hour average measurement of 35.5 micrograms per cubic meter or higher is an exceedance of the standard.

Daily Measurements

The main number in each cell of this chart shows the hourly average concentration of PM2.5.  

The smaller number in the colored box at bottom right is a comparison with the recorded concentration 24 hours earlier. When the box is red, that means the concentration is higher than it was at the same hour on the previous day.  When the box is blue, that means the concentration is lower.

The columns at far right show the highest hourly average concentration and the 24-hour average concentration of PM2.5 for the day.

* At this time, PM2.5 measurements at the Napa Valley College location are for informational purposes only.

Northern Zone
Stations Saturday, October 21, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 MaxAvg
Napa
12
+8
9
+4
16
+9
14
+7
13
+3
19
+6
9
-7
14
+3
9
-3
13
+2
13
+3
10
-4
8
-3
1912.2
Napa - Napa Valley College
8
+2
7
-2
5
+0
7
+3
8
+0
9
-3
13
+3
9
-1
9
+2
10
-1
9
-1
10
+3
8
+1
138.6
San Rafael
8
+3
7
+2
3
-4
3
-4
4
-1
7
+0
8
+1
6
-1
6
+2
8
-11
6
-15
4
-3
4
-4
85.6
Sebastopol
3
+2
5
+3
4
+1
4
+1
3
+0
3
+0
7
+3
5
+5
5
+3
5
+3
4
-2
2
-5
3
-2
74
Vallejo
7
+2
7
+1
7
+1
7
+1
10
+5
13
+6
15
+7
11
+3
11
+6
14
+11
8
+4
4
-1
10
+5
159.5
Coast & Central Bay
Stations Saturday, October 21, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 MaxAvg
Berkeley Aquatic Park
7
+3
5
-1
4
-1
2
-1
11
+6
11
+3
10
+1
9
-1
10
+2
7
-1
5
-3
9
+2
11
+5
117.7
Laney College
11
+5
9
+1
8
-1
8
-2
8
-1
9
-7
8
-7
9
-5
7
-7
6
-7
8
-4
11
-2
13
-1
138.8
Oakland East
3
+3
7
+3
6
+3
3
-3
5
+0
4
-1
5
-2
5
-2
4
-3
2
-4
3
-1
4
+4
6
-2
74.3
Oakland West
13
+6
11
+8
11
+3
6
-5
8
+0
11
-4
9
-8
9
-3
8
-6
11
+3
10
+4
11
-1
10
+1
139.8
San Francisco - Arkansas St.
3
-1
4
-1
6
+3
7
+4
8
+0
6
+0
5
-2
3
-4
-1
-12
0
-6
6
+1
4
+3
0
-2
83.9
San Pablo - Rumrill
7
+5
5
+3
4
-2
4
-2
5
-4
8
-1
7
-4
13
+6
10
+4
9
+1
8
+0
5
+0
7
+7
137
Eastern Zone
Stations Saturday, October 21, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 MaxAvg
Concord
11
+5
10
+4
7
-1
8
+1
9
+1
8
+2
11
+6
17
+6
6
-4
8
-3
10
+0
11
+2
10
+3
179.6
Livermore - Rincon Ave.
3
+0
1
-8
4
+1
-6
-8
28
+26
6
+0
6
-1
8
+3
9
+5
7
+1
4
-3
2
-3
286
South Central Bay
Stations Saturday, October 21, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 MaxAvg
Redwood City
1
-1
4
+5
6
+6
7
+8
22
+26
1
-14
-1
-6
21
+16
7
+4
4
-1
5
-3
8
+0
7
+1
227
Santa Clara Valley
Stations Saturday, October 21, 2017 Daily
Hourly PST 01234567891011121314151617181920212223 MaxAvg
Gilroy
3
-1
3
+5
0
+1
1
+1
2
+1
4
+0
7
+1
10
+0
13
+2
12
+4
8
+1
7
+0
5
+0
135.7
San Jose - Jackson St.
1
+1
3
+2
4
+3
4
+2
4
+1
6
+5
9
+6
23
+18
5
+1
4
+0
0
-4
0
-3
2
+0
235
San Jose - Knox Av
5
+3
5
+3
11
+10
8
+3
8
+0
9
+2
9
-3
7
-3
7
+0
5
-1
5
+2
4
+3
10
+3
117.1
Spare the Air Status
Spare the Air Status
  • Saturday,
    10/21

    No Spare the Air Alert in Effect

  • Sunday,
    10/22

    No Spare the Air Alert in Effect

10/17/2017