§
Mr. Baldry
The table shows the average figures for the months of June and December at the central London site, With the maximum hourly level reached in that month for carbon monoxide (CO), sulphur dioxide (SO2), ozone (O3)and nitrogen dioxide (NO2). No measurement data in this format are available for carbon dioxide.
CO ppm |
|
Average |
Maximum |
Year |
June |
December |
June |
December |
1980 |
0.6 |
0.9 |
3.1 |
4.6 |
1981 |
0.7 |
1.7 |
3.8 |
7.1 |
1982 |
0.6 |
1.0 |
3.3 |
3.4 |
1983 |
— |
1.0 |
— |
6.2 |
1984 |
0.8 |
1.4 |
4.3 |
11.5 |
1985 |
0.5 |
0.7 |
3.2 |
4.0 |
1986 |
0.7 |
— |
3.8 |
— |
1987 |
— |
— |
— |
— |
1988 |
0.7 |
1.5 |
2.5 |
8.1 |
1989 |
0.9 |
1.9 |
2.8 |
13.1 |
1990 |
0.9 |
1.5 |
4.2 |
11.7 |
1991 |
1.1 |
2.2 |
3.6 |
13.3 |
SO2 ppb |
|
Average |
Maximum |
Year |
June |
December |
June |
December |
1980 |
26 |
21 |
150 |
152 |
1981 |
15 |
58 |
98 |
339 |
1982 |
24 |
36 |
281 |
238 |
1983 |
17 |
34 |
142 |
133 |
1984 |
16 |
16 |
295 |
379 |
1985 |
7 |
7 |
31 |
16 |
1986 |
16 |
16 |
178 |
68 |
1987 |
7 |
14 |
47 |
153 |
1988 |
6 |
14 |
76 |
57 |
1989 |
10 |
15 |
125 |
190 |
1990 |
9 |
11 |
86 |
72 |
1991 |
5 |
18 |
54 |
144 |
342W
O3 ppb |
|
Average |
Maximum |
Year |
June |
December |
June |
December |
1980 |
14 |
2 |
42 |
10 |
1981 |
13 |
2 |
63 |
16 |
1982 |
— |
5 |
— |
23 |
1983 |
13 |
— |
49 |
— |
1984 |
17 |
1 |
68 |
7 |
1985 |
22 |
12 |
84 |
59 |
1986 |
21 |
5 |
105 |
26 |
1987 |
6 |
3 |
35 |
21 |
1988 |
10 |
4 |
59 |
29 |
1989 |
19 |
5 |
108 |
33 |
1990 |
12 |
7 |
67 |
30 |
1991 |
13 |
4 |
47 |
18 |
NO2 ppb |
|
Average |
Maximum |
Year |
June |
December |
June |
December |
1980 |
32 |
34 |
88 |
72 |
1981 |
— |
42 |
— |
103 |
1982 |
40 |
38 |
98 |
78 |
1983 |
37 |
39 |
101 |
114 |
1984 |
42 |
— |
156 |
— |
1985 |
34 |
29 |
108 |
75 |
1986 |
33 |
36 |
141 |
77 |
1987 |
37 |
38 |
90 |
239 |
1988 |
33 |
33 |
100 |
92 |
1989 |
40 |
34 |
108 |
125 |
1990 |
28 |
39 |
86 |
150 |
1991 |
34 |
56 |
84 |
423 |