Evening star. [volume] (Washington, D.C.) 1854-1972, 1902-11-13
STREET VENTILATION.
F1ues to Garry Off Foul Air of City
Highways.

From the Scientific American.
The solution Of the problem of the purifi-
cation of the subsurface atmosphere known
as ground air must sooner or later become
vital to a citys inhabitants. That the state
of the public health may be set forth as the
chief asset of a communitys prosperity Is
shown in the presence of an epidemic.
Thanks to the high development which SAN
itary engineering has reached, sewerage
and ground drainage are well-nigh perfe ct.
The question of surface and ground-ar
drainage, while backward in its develop
ment, becomes of none the less Importance
to the engineer, and though dealing with
the mixtures Of gases they are subject to
the governing laws of flow and diffusion as
IS the more stable liquid. In New York
city, owing to the great concentration of in
habitants, combined with the spirit Of pro-
gress of our times. manifested by blocks of
high buildings, which change streets into
narrow lanes, the many systems of pipe
galleries and tunnels for water, gas. steam,
sewage, telephone telegraph and light and
heat wires, besides the rapid transit pas
senger tunnel soon to be installed all tend
for the most extreme conditions for an i'm
pressive exhibition of the evil. Street tun-
nels, Easements and buildings having an in
innate connection, the free circulation Of
all that is harmful is unhindered
The deleterious substances which are the
chief sources of ground-asr contamination
comprise. besides dry, dust-borne particles
and matter held in suspension in water
vapor, the effluvia arising from the decom
position of organic matter and the more
demonstrable posons found in leaking illu-
minating gas mains. According to the
statement of one sanitary expert, it is gen.
orally acknowledged by the gas companies
of our city that fully one-third of the whole
quantity of gas manufactured by them
leaks away before delivery through the
house meters occurs, They recognize that
it Is far cheaper to manufacture this large
excess of gas and allowing it thus unheeded
to eontaminate the lower atmosphere of
streets and buildings than to attempt to
make tight mains or house connections.
Furthermore, 1t has been demonstrated that
the water-gas now so largely employed for
lighting and heating, which is principally
composed of carbon monoxide, is injurious
and, indeed, becomes deadly when present
in a quantity equal to L per cent of mix
ture. The custom of street dissemination
of what may be called gas sewage is pro-
portionately as injurious to healthy living
as though water sewage was left to decom-
pose In the cityS cutters.
Carbon monoXide being odorless, 1t be-
comes doubly dangerous; for it not only
suffocates mechanically, but acts directly
as a true poison to the human system. Col
lections of mixed gases take place to such
an extent that manhole explosions are not
of infreQuent occurrence, and the several
companies occupying tunnel space In the
streets are forced to secure conduit covers
against gas pressure by boiling.
The plan to be submitted for the carrying
off of contaminated ground air consists Of
system of fues, connected at sufficient
intervals with subcellar and tunnel cham
Der compartments. When practical, Chin
neys constructed Of metal piping or Of brick
may be built in connection with buildings.
In districts where this is impossible they
may take the form of ornamental columns.
According to the observations of DR.. ORA
per- director New York state weather bu-
reau,. the average yearly wind velocity
over New York city Is seven miles an hour.
This speed being apparent at mean height
of seventy feet above ground level, 1t be-
comes thus entirely practical to employ the
means which have been suggested for the
removal of an insidious present and grow
ing evil.