Weekend/Weekday Ozone Observations in the South Coast Air Basin

log NOx (ppb)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
VOC/NOx
2.5
5.0
A
7.5
10.0
12.5
15.0
A
L
U P
L U
P
A
L
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
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
2.8
2.6
2.4
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC ( ppbC )
HO (ppt)
2.8
2.6
2.4
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
log VOC ( ppbC )
HNO3 (ppb)
90
81
log NOx (ppb)
2.2
2.0
1.8
1.6
1.4
1.2
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
0.18
0.48 0.6
log NOx (ppb)
2.2
2.0
1.8
1.6
1.4
1.2
P
L U
P
A
L
A
U A
L
72
5463 45 36
27
18
9
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 1.4-19 Plots of VOC/NO x ratio, ozone production efficiency (∆[O 3 ]/(∆[HNO 3 ] + ∆[Organic
Nitrates]), hydroxyl radical, and nitric acid 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. The yellow squares
represent Wednesday and the dark red dots represent 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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