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47
The following tables show the average and highest smoke and S02
concentrations for the period of operation for the four stations, and
graphs based on these figures are also given for easier comparison. The
figures marked with an asterisk are approximate estimated averages, an
insufficient number of daily readings having been taken during these
periods.
It is interesting to compare this with the results of experiments
conducted in conjunction with the Warren Spring Laboratory at Hackney
and Sheffield, where the average reduction of smoke to be expected as a
result of the operation of Smoke Control Orders was of the order of
16 per cent, or an average quantitative reduction of 25 microgrammes per
cubic metre per day. The sulphur dioxide reduction in these experiments
was about 15 per cent.
There is no doubt that a great deal of useful information will become
available to the D.S.I.R. as a result of the National Survey and the help
given by pupils and teachers at the two schools and by the laboratory staff
of the factory, in operating these local stations, has been greatly
appreciated.