Weekend/Weekday Ozone Observations in the South Coast Air Basin

2.8
2.6
Ozone (ppb)
2.8
2.6
VOC/NOx
2.4
2.4
log NOx (ppb)
2.2
2.0
1.8
1.6
1.4
1.2
80
A
L
U P
L U
P
A
L
A
280
200
160
400
360
log NOx (ppb)
2.2
2.0
1.8
1.6
1.4
1.2
2.5
5.0
A
7.5
10.0
12.5
15.0
A
L
U P
L U
P
A
L
1.0
120
1.0
0.8
L
A
Los Angeles North Main 1987
Azusa 1987
0.8
L
A
Los Angeles North Main 1987
Azusa 1987
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC ( ppbC )
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC ( ppbC )
log NOx (ppb)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
O3 Production Efficiency
A
L
U A
P
L U
P
A
L
2
4
6
8
10
12
14
log NOx (ppb)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
HO (ppt)
0.6
L
A
L
U A
P
L U
0.24
0.12
P
0.18
A
0.30
0.36
0.42
0.12
0.48 0.18
0.6
1.0
0.8
L
A
Los Angeles North Main 1987
Azusa 1987
1.0
0.8
L
A
Los Angeles North Main 1987
Azusa 1987
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC ( ppbC )
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC (ppbC)
Ozone (ppb)
Figure 3.5-1 Plots of ozone, VOC/NO x ratio, ozone production efficiency (∆[O 3 ]/(∆[HNO 3 ] + ∆[Organic
Nitrates]) and hydroxyl radical superimposed on a color O 3 EKMA plot. Also plotted are mixing ratios
for NO x and NMHC during the summer of 1999 and 2000 with error bars representing one standard
deviation from the average with the labels (A) representing Azusa, (L) representing Los Angeles – North
Main, (P) representing Pico Rivera and (U) representing Upland and the yellow squares representing
Wednesday and the dark red dots representing Sunday. The error bars are not symmetrical because of the
logarithmic scale. The two white dots labeled (L) and (A) represent the average conditions for Los
Angeles – North Main and Azusa during 1987, respectively.
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