ABSTRACT
The initial efforts at understanding the hazards of automotive exhaust began in California in the late 1940s with political and scientific attention being paid to photochemical reactions in the atmosphere between hydrocarbons and nitrogen oxides emitted in automobile
exhaust. Professor Haagen-Smit of the California Institute of Technology1 showed that some hydrocarbons and nitrogen oxides endemic to automobile exhaust reacted in sunlight to produce oxidants, including ozone, which caused cracking of rubber and irritation of the eyes [1]. A concurrent investigation by the Los Angeles Air Pollution Control District verified that aerosols and mists could be produced photochemically by the polymerization of photooxidation products of exhaust hydrocarbons and laid the scientific basis for a serious examination of the composition and health impact of automotive exhaust [2]. These two studies provided the necessary impetus for the eventual development of the automotive catalytic converter.
