Cigarettes are manufactured to close tolerances using strict quality control procedures. However, all the constituents involved in the manufacture are derived from natural products
(tobacco, cigarette paper, tipping, etc.) and this results in a final product which is intrinsically variable. The complexity does not finish here as the cigarette is converted during smoking to cigarette smoke. Cigarette smoke is a complex mixture consisting of many individual chemical constituents. These compounds exist as gases, vapours and condensed aerosol particles. Additionally, various aging processes, together with diffusional and intersolubility effects, start occurring immediately after the formation of the smoke to further complicate its composition.
