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MEASURMENTS OF ATMOSPHERIC POLLUTION
Measurements of the smoke and sulphur dioxide content of the atmosphere are taken
by most local authorities at various sites in their areas in conjunction with the
Department of Scientific and Industrial Research.
Readings of the instruments are taken daily and the reports submitted monthly to
the Department. Published lists of the readings are then issued.
By this means, not only can a local authority note the progress it is making in
its efforts to produce a cleaner atmosphere but it can also make comparisons with
local authorities of all types throughout the country. The relationship between air
pollution and the incidence of respiratory and other diseases in an area can also be
considered.
The dust and grit which is sometimes emitted from industrial chimneys, whilst
it may be a serious nuisance to the occupiers of premises on which it falls, is of
no great significance to public health as the particles are too coarse to reach the
human lung. The smoke, however, which is extracted from the atmosphere and measured
in the smoke-measuring apparatus consists of very small particles, small enough to
remain airborne indefinitely and capable of passing the natural defence mechanisms
of the nose and throat and reaching the lungs. These particles come principally
from the smoke of domestic chimneys burning bituminous fuel.
For a period of 24 hours, air containing this smoke is drawn through a filter
in the measuring apparatus upon which the particles are collected. The darkness of
the stain on the filter pad is them measured in a reflectometer and from this
reading is calculated the concentration of smoke in the air.
Sulphur dioxide, which is derived from the sulphur present in coal and in
fuel oils, is an important gaseous pollutant and its measurement is recorded as,
combined with smoke particles, it can seriously injure buildings and fabrics. There
is, as yet, no known economical method available of removing sulphur from fuel or
from flue gases.
This Council operates three smoke measuring stations at sites approved by
the Department of Scientific and Industrial Research i.e. at Golders Green, Mill
Hill and Edgware Branch Libraries.
The Director of the Department of Scientific and Industrial Research advised
a change in the method of recording the measurement of smoke and sulphur dioxide
in order that an international standard of comparison could be obtained, and the
daily averages of smoke and sulphur dioxide are now recorded in microgrammes per
cubic metre.
In this report the records for the years 1957 to 1960 have been converted
to these new standards and the tables show the gradual change that has occurred
since smoke and sulphur dioxide measurements were first made in Hendon in 1957.
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