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Some firms who have already made the alterations to their plant claim that they have lowered
the overall cost of their heating requirements, although mild winter conditions could account for
some of this.
In order to effectively bring the Act into operation it was found necessary to commence field
work in the following manner:-
(1) To carry out a survey of all premises to ascertain fuel usage and type, the capacity of
the furnace and other relevant matters.
(2) To increase the monitoring facilities of particulate matter and SO2. This is at present
being carried out in two ways:-
(a) By the installation of additional standard volumetric samplers; and
(b) By careful observation of weather conditions, particularly periods of temperature
inversion.
The facts so obtained are now correlated and an enlightening picture is beginning to form.
It is necessary to know the amount and nature of the emissions in question, the initial and
local aerodynamic influences on the movement and dispersion of the effluent plume, and the
subsequent dispersion in the atmosphere as a whole. Meteorological considerations enter into
some of these factors.
It has been found that the work concerned with this survey is time-consuming and that the
full facts of the case will not be known for some time to come, but the results so far are encouraging
and would suggest that there has already been some reduction of S02 pollution.
Because of the additional responsibilities placed on the Department to implement the provisions
of this Act and other Clean Air legislation, some of which commenced on January 1st, a
specialist section was set up, dealing, among other things, with the monitoring of sulphur dioxide
levels, the survey of boiler plants, the observation of weather conditions, the consideration of
proposed chimney heights, detection of smoke nuisance from premises and demolition and reconstruction
sites, the ascertainment of boiler efficiencies for the purpose of eliminating soot and
acid smuts, and the giving of technical advice about fuels and the operation of plant.
Two of the staff were placed on this work in a full-time capacity and other Inspectors devote
part of their time to these duties.
Much of the work carried out by this section is of a routine nature and, as such, can be
planned to give the maximum effect for the furtherance of environmental pollution control. It will
be appreciated that although this work is organised on a routine basis specialised technical skill
is required. One factor is that the City was the first local authority in Britain to obtain legislation
for controlling sulphur in fuel oil, so that practical work carried out in this field is entirely new
and there is little experience to draw upon.
Chimney Height, Section 6, Clean Air Act, 1968
During the year, 19 applications for the approval of chimney height were received and considered.
These applications dealt exclusively with furnaces and chimneys that were renewed or
altered in existing premises. Prior consultation was encouraged between the Applicant, the
Planning Officer and this Department. This avoided duplication of applications and ensured a
common policy between departments.
The Chimney Height Memorandum provides a workable minimum limit to the height of chimneys
and ensures that, together with the provisions of the Clean Air Act, 1968, the chimney height is
taken to such a height as to disperse the flue gases with a minimum nuisance to the surrounding
locality. Correctly placed chimneys can help to minimise ground-level concentration of sulphur
dioxide and other unpleasant and noxious flue gases. When investigating these applications
considerations must be given to:-
(a) the purpose of the chimney;
(b) the position and description of buildings near it;
(c) the levels of the neighbouring ground;
(d) any other matter requiring consideration in the circumstances.
An interesting facet of this problem is that of gas-fired installations which have a fandiluted
flue. The reason for this method of discharge of the products of combustion is that the
flue gases are discharged in a diluted condition at low level and allegedly obviate the necessity
of a costly chimney. Although there is little sulphur-dioxide pollution from this source, there are
other offensive gases that may be emitted. Owing to the congested conditions prevailing in the
City, it is felt that this kind of discharge is undesirable, and the outlets are now required to be
taken to a more realistic height.
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