The number and duration of the fogs were somewhat
unusual, and have led to their chemical examination at Manchester
by Dr. G. H. Bailey, J. B. Cohen, Mr. Hartog (of
Owen's College), and Dr. Tatham, who have reported thereon.
The report shows a great increase in the number of deaths
from inflammatory diseases of the lungs during the prevalence
of the fogs which were impregnated with sulphurous acid, tar
acids, and other injurious matter. Taking the normal number
of deaths per week in Manchester from the above named causes
at 60, they found that during the exceptionally dense fogs
which preceeded Christmas, this number went up to more than
200. In London, the number of deaths from inflammatory
diseases of the lungs which previously to the fogs were only 300
rose during and immediately following the fogs to 927 in the
week ending January 3rd, 1891. These fogs were accompanied
by a long continuance of cold weather, so that the whole of the
increased number of deaths must not be entirely attributed to
them. The sulphurous acid of the air arises wholly and solely
from the combustion of coal, which ordinarily contains from 1
to 2 per cent of sulphur. During three day's fog, the experiments
showed that in the vicinity of the Infirmary there was
carried down per square mile nearly 6 cwt. of sulphuric acid,
while at Owen's College the amount was over 4 cwt. The
"blacks" amounted to over 2 tons, and the hydrochloric acid
to above 2 cwt. per square mile. Experiments on the air of
London during fogs, made some years ago, showed that nearly
the same amount of acids, and a large quantity of tar products
were contained in the air. It is therefore advisable that every
one who can should keep indoors during foggy weather. The
number of fogs observed during the winter of 1890-91 was nearly
double the average.
I remain, Gentlemen,
JOHN W. TRIPE, M.D.,
Medical Officer of Health.
April 8th, 1891.
Beceived and ordered to be printed and circulated in the
April 8th, 1891.