Geology Reference
In-Depth Information
H
þ
O
2
þ
M
-
HO
2
þ
M
(2.12)
HO
2
þ
NO
-
OH
þ
NO
2
(2.19)
NET: CO
þ
2O
2
þ
hn
-
CO
2
þ
O
3
(2.29)
Similar chain reactions can be written for reactions involving RO
2
.In
contrast, when relatively little NO
x
is present, as in the remote atmos-
phere, the following cycle can dominate over ozone production leading
to the catalytic destruction of ozone, viz
HO
2
þ
O
3
-
OH
þ
2O
2
(2.15)
OH
þ
CO
H
þ
CO
2
-
(2.11)
H
þ
O
2
þ
M
-
HO
2
þ
M
(2.12)
NET: CO
þ
O
3
-
CO
2
þ
O
2
(2.30)
Clearly, there is a balance between photochemical ozone production and
ozone loss dependent on the concentrations of HO
x
and NO
x
. Figure 11
shows the dependence of the production of ozone on NO
x
taken from a
numerical model. There are distinct regions in terms of N(O
3
) vs. [NO
x
]
8
C
6
4
B
2
0
A
-2
1
10
100
1000
NOx (pptv)
Figure 11 Schematic representation of the dependence of the net ozone (N(O
3
))
production (or destruction) on the concentration of NO
x
