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London County Council.
EXAMINATION OF THE ATMOSPHERE OF THE CENTRAL
LONDON RAILWAY.
PART I.— REPORT BY THE CHEMIST.
In accordance with the instructions of the Parliamentary Committee of the 23rd January, 1902,
the atmosphere of the Central London Railway has been examined chemically, physically, and
bacteriologically.
The chemical examination was commenced on March 10th, and the last samples were collected
on October 24th. During the period between these dates 88 samples were collected and examined.
The first sample for the bacteriological examination was taken by Dr. Andrewes on March 14-th
and the last on June 19th. The results of the bacteriological examination are fully dealt with in the
report presented by the medical officer. Dr. Andrewes collected samples for the bacteriological
examination at the same time and place as the chemist collected samples for the chemical examination.
The days on which this joint collection was made are marked in Table I. with an asterisk. It
will be seen that in most cases the conclusions as to the quality of the air which were arrived at from
the chemical examination are in accord with those indicated by the bacteriological examination.
The chemical examination consisted in the determination of the amount of carbon dioxide
(carbonic acid) in the air, and of the amount of oxygen absorbed from permanganate by the organic
matter present in the air.
I have set out in Table I. the results of the examination of the 88 samples of air, together with
the date, time and place of their collection. The results of the examination of the outside air of the
street in the immediate neighbourhood where the samples were taken in the railway are also included
in this table. For the purpose of showing the relative amount of contamination of the air at
different points on the railway, I have also set out the results of the examination in further tables,
Nos. II. to VII.
The carbon dioxide was estimated by Pettenkofer's method, glass bottles of about 5.5 litres
capacity being filled with the air of the locality by blowing air through them by means of handbellows.
The organic matter was estimated by collecting samples of the air in a similar manner and then
introducing into the bottles solution of potassium permanganate acidified with sulphuric acid. The
amount of permanganate which underwent change was estimated by the usual process of titration.
Table I. shows that the quantity of carbon dioxide in the air of the Central London Railway
varied considerably, whilst the quantity present in the outside air varied only to a slight extent.
The amount of organic matter present in the air of the tube and in the external air underwent
considerable fluctuation.
Table II. shows the number of volumes of carbon dioxide in 10,000 volumes of air collected
in the stations, together with the number of volumes of carbon dioxide in 10,000 volumes of the air
collected outside the station a few minutes after the samples were taken in the station.
Table III. shows the number of volumes of carbon dioxide in 1.0,000 volumes of air collected
in the passages, as compared with the quantity present in the outside air.
Table IV. gives the determinations of carbon dioxide in the air in the lifts and tunnels, as
compared with those made in the fresh air.
Table V. shows the quantity of carbon dioxide in the air of the carriages, as compared with the
quantity in the fresh air outside the station.
Table VI. contains the maximum and minimum amounts of carbon dioxide per 10,000 volumes
of the air collected at the different places on the railway.
Table VII. For the purpose of comparison I have included a seventh table, which show3
the volume of carbon dioxide in 10,000 volumes of air collected on railways other than the Central
London Railway.
A consideration of the results obtained from the examination of the samples of air collected on
the Central London Railway shows that, generally, the quantity of carbon dioxide was highest in the
air of the carriages ; but that, contrary to what might reasonably have been. expected, the largest
quantity was not found in the carriages where smoking was allowed. The highest proportion of
carbon dioxide (14.7 volumes in 10,000 of air) was present in the air of an ordinary passenger
carriage on October 10th. The smallest quantity found was that present in an empty carriage on
October 16th, viz., 9.6 volumes in 10,000 volumes of air.
The air in the passages leading to and from the stations was generally better than that in the
lifts. On one occasion (June 6th) the air in the lift at the Oxford-circus station contained 15.2 volumes