The toxicity of fumes from a diesel engine under four different running conditions.

It has been suggested that fumes from diesel engines make an important contribution to atmospheric pollution. This is probably because they are sometimes highly irritant and sometimes very smoky. It is well known that, because of their comparatively low carbon monoxide content, these fumes are much less lethal than those from petrol engines. The leading work on diesel fumes has been done by the U.S. Bureau of Mines. Holtz, Berger, Elliott, and Schrenk (1940) analysed the fumes from engines in proper mechanical conditions, plotting the carbon monoxide, nitrogen oxides, and aldehyde content against fuel-air ratio. The present work was directed to ascertaining what were the main toxic constituents of diesel fumes. In order to do this animals were exposed to the fumes and at the same time the concentration of various constituents of the fumes was determined; pathological investigations were subsequently carried out on the exposed animals. In this paper nitric oxide is designated NO, and nitrogen dioxide NO2. For conversion of parts per million to mg./m3 factors valid at 20°C. have been used.