A gate possible carcinogenic activity of air pollutants and the contribution that automobile exhaust may make in this respect, we are undertaking chemical analyses of established and suspected carcinogenic and cocarcinogenic substances. The present report represents the analytic results of the isolation and identification of polynuclear aromatic hydrocarbons present in the exhaust from a gasoline engine.
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Kotin and co-workers89 9 identified, in the particulate phase of exhausts from both gasoline (Ford V-8) and diesel engines, 6 known polynuclear hydrocarbons and have shown their differential formation with respect to engine speed and load. In addition, an unknown compound was detected. The isolation and identification of these hydrocarbons was accomplished by collecting on filter paper particulates from the engine exhaust and extracting the filter with benzene. T h e extract was then chromatographed on activated alumina; the same known hydrocarbons and benzo[k]fluoranthene were also isolated by Reuter et aL13 from diesel exhaust using an analytic technique similar to that just mentioned. Lyons10 and Lyons and Johnstonell reported an additional 8 aromatic hydrocarbons in gasoline exhaust, as well as in diesel exhaust. These particulates from the engine exhaust were collected in hemp sacks, the sacks and From the Section of Epidemiology, Division of Preventive hledicine, Sloan-Kettering Institute for Cancer Research, 444 E. 68th St., New York 21, N.Y. The authors are most grateful and appreciative of the excellent assistance in the preparation of the ultraviolet absorption and fluorescence spectra given by Mr. E. Theisz. The authors are indebted to the General Motors Corporation and to the Research Laboratories of the General Motors Corporation for assistance in providing samples of hydrocarbon condensate extracted from automobile engine exhaust. The ben~o[u]pyrene-6-C~~ used in the tracer study was a gift from Dr. C. Heidelberger, Madison. Wis.