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104
1. Smoke concentrations have decreased by 80 per cent since 1958
in central London.
2. Sulphur dioxide concentrations have decreased by 40 per cent
since 1958 in central London.
3. Sunshine in central London in December has increased by 70
per cent since 1958.
4. Winter visibility has increased threefold since the Act came
into force.
5. 138 bird species can now be seen in London, compared with
less than half that number ten years ago.
The readings from our own sites show clearly that the Borough
has shared in the benefits of cleaner air.
Grit and Dust.
Two deposit gauges for the monthly measurement of grit and
dust fall are located at Canbury Gardens and Tiffin Girls' School,
Kingston upon Thames. The deposit measured at the Canbury Gardens
site decreased from 17 tons per square mile in 1968 to 15 in
1969, an improvement which is probably attributable to the better
quality fuel now being used at the Power Station.
11. RODENT AND INSECT PEST CONTROL.
It is pleasing to be able to report a further reduction in the
number of premises found to be infested by rodents. The figure of
1.7% of the premises in the Borough where rats were found compares
with a national average for urban areas of 2.0% This was the
figure for the Borough during the first year of amalgamation.
Complaints continue to be received with regard to pigeons and
it is to be hoped that people can be persuaded not to encourage
the formation of flocks of the birds by feeding to excess.
Squirrels are also a nuisance in certain parts of the Borough
and the department prepared an advisory leaflet on the subject
similar to the one produced last year on Wasps which proved to be
very successful.
During the year 20 Field Officers of the Ministry of Agriculture,
Fisheries and Food, received part of their training in the Borough
together with a Crop Storage Specialist of the United Nations Food
and Agriculture Organisation.
Part of the Ministry's new film on Rodent Control was made in
the district in co-operation with members of the staff of the
department.