The composition of cigarette smoke: A catalogue of the polycyclic aromatic hydrocarbons

Abstract

Classified as toxicants in many of the substances to which humans are exposed are the polycyclic aromatic hydrocarbons (PAHs). Such exposures include air pollutants from a variety of sources, foodstuffs and beverages, and tobacco smoke. Since the early 1950s, the composition of the latter has been more completely defined than that of any other consumer product. Nearly 4800 components have been identified in tobacco smoke and among these are over 500 PAHs either completely or partially identified. Because of the tumorigenicity of many PAHs, much research has been conducted in attempts to define the relationship between the PAH structures and their specific tumorigenicities in laboratory animals. None of the theories to date completely answers all the questions. As a prelude to an attempt to develop a more reasonable PAH structure-tumorigenicity relationship, the PAHs completely or partially identified in cigarette smoke have been catalogued. In the catalogue, they are categorized as bicyclic, tricyclic, tetracyclic, etc. with each group subdivided into all-benzenoid PAHs and cyclopentanoid-benzenoid PAHs. Another tabulation includes the PAHs considered in several previous studies on structure- tumorigenicity relationships, studies that dealt primarily with all-benzenoid PAHs.