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111
The Ministry of Housing and Local Government published in
August 1967 a Memorandum entitled "Grit and Dust", dealing with
the measurement of emissions and recommending maximum levels of
emission. All solid fuel and oil-fired furnaces in the
Borough comply with the standards suggested.
Chimney Heights.
Five plans were submitted for determination of chimney
heights under Section 10 of the Clean Air Act, 1956. In nine
further cases advice was given where new chimneys, exempted from
the provisions of Section 10, were being erected. A revised
Memorandum on chimney heights has been issued by the Ministry of
Housing and Local Government, this extends the range of application
of the original Memorandum to include small installations
having a sulphur dioxide emission of 3 lbs. per hour and upwards
allowing for a minimum chimney height of 25 feet instead of 40
feet as formerly.
Until practical means are generally available for the
removal of sulphur from fuel or sulphur oxides from flue gases,
some control over the heights of new chimneys is essential in
order to keep within reasonable limits the concentration of
sulphur dioxide at ground level. Larger supplies of low sulphur
fuel oils are now becoming available, but a much greater effort
is needed in this direction. It is unfortunate that shops,
offices and blocks of flats are exempted from the provisions of
Section 10 which deals with the height of new chimneys, but legislation
is at present before Parliament to widen the scope of this
Section and improve administrative procedure.
Recording of Air Pollution.
Instruments for measuring the amount of smoke and sulphur
dioxide in the air are maintained at the Guildhall, Tiffin Girls'
School, Alpha Road Public Health depot and at a site in Maiden
Road, New Maiden. These operate continuously, and at the first
three sites readings are taken five times a week. A more
sophisticated sampling instrument known as the 8-port sampler has
been constructed by a member of the staff and is now in use at the
Maiden Road site. This provides daily readings, but only needs
visiting once a week. The figures are submitted monthly to the
Ministry of Technology's Warren Spring Laboratory for inclusion
in the national survey of atmospheric pollution.
It is felt that readings have been taken over a long enough
period to enable some attempt to be made at interpreting them.
A major difficulty is that weather conditions have a far greater
influence on the results than any other factor. For example,