Environmental Engineering Reference
In-Depth Information
An additional analysis of background ozone concentrations was performed on
selected days when the 8 h ozone concentrations, with anthropogenic emissions
included, exceeded 70 ppb
. Table 1 s
hows lower contributions from background
ozone by typically 1-3 ppb. This could be caused by more dry deposition with
slow moving high pressure systems that are typical during high ozone episodes.
Table 1.
Background ozone concentration (ppb), May-September 2005
Subdomain Average
Max
Min
Standard
deviation
Averaged on high
concentration days
1
31.2
44.0
21.1
4.4
30.0
2
34.0
43.9
23.1
4.2
32.7
3
32.3
43.2
19.3
4.2
29.5
4
33.1
46.0
21.9
4.3
32.4
5
32.4
42.8
16.8
4.6
29.9
6
30.8
43.3
16.5
4.4
28.4
7
30.3
45.3
18.2
4.3
27.7
8
29.6
44.7
18.7
4.6
25.1
9
30.4
44.3
18.5
4.1
23.7
Distribution of background ozone concentration in
subdomain #5 SW Ontario
25.0
20.0
15.0
10.0
5.0
0.0
18
20
22
24
26
28
30
32
34
36
38
40
42
44
ozone concentration, ppb
Fig. 2.
Frequency distribution of background ozone concentration in South-Western Ontario for
ozone season May-September 2005
