Composition of Urban Particulate
Air Pollutants
The National Air Sampling Network
JAMES P. LODGE, JR.
Chief, Chemical Research
Robert A. Taft Sanitary Engineering Center
U. S. Public Health Service
Cincinnati, Ohio
One of the characteristics of living organisms is the production of
waste products, and man being the most complex living organism, produces the most complex assortment of wastes. If any organism is placed
in an environment such that its used materials accumulate indefinitely,
it will die and man is no exception. The difference lies rather in the
fact that man can to some extent control his environment, and hence
to some extent control the dispersal of his wastes.
For such disposal man depends on the four elements of the ancients:
earth, to bury them; water, to carry them ultimately to the sea; fire
and other chemical changes, to convert them to less toxic forms; and
air, to dilute them and carry them away. The last two methods shall be
the concern here; they are obviously related, since many of the combustion products are themselves carried off by the air.
Man's mastery of his environment is, however, not complete. There
are times when this ocean of air stands still; when materials introduced
into it remain near the point of release; when their concentration in
the surrounding air becomes high enough to cause discomfort or danger
to man, or to certain of his symbionts. This condition is called air
pollution. Since there still is no control over meteorological phenomena,
man's only resource is to decrease or stop completely, his output of wastes
until the conditions are more favorable for their release. It is the job of
the research worker in air pollution to determine what waste materials
are being released and which of these are reaching dangerous levels. It is
the job of the engineer to decrease the emission of these, if possible, without stopping the process in which these arise, or failing this, to program
the entire process giving rise to these effluents in accordance with
meteorological conditions.
That the attempts at control have not yet been adequate in keeping
up with the increasing industrialization is attested by a number of dead
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