Tobacco smoke is an aerosol contain

Tobacco smoke is an aerosol containing an extremely complex mixture of chemicals [1]. It consists of liquid/solid droplets, called the particulate phase (PP), suspended in a mixture of gases and semi-volatiles – the vapor phase (VP). Although the majority (95%) of whole cigarette smoke is gaseous phase by weight, with the remainder (5%) being particulates [2], the latter part contains most of the 6000+ identified compounds [3]. Based on gas chromatographic (GC) scans, various investigators have estimated that for each component identified in tobacco smoke there were 5–20 components present at extremely low levels that have not yet been identified, and the total number of tobacco smoke components might reach up to 100,000 [4].