Smokers' lung cancer risk related to the cigarette-generated mainstream particles

Cigarette smoking represents the main cause of lung cancer events. This is due to the carcinogenic compounds condensed onto particles generated during the combustion process and then inhaled through the mainstream side (i.e. the cigarette filter side) of the cigarette. The present paper applied a novel lung cancer risk model, able to take into account both ultrafine and coarse particle toxicity, to the particle concentration levels measured in the mainstream aerosol of cigarettes in order to provide a useful provisional tool for testing different smoking scenarios. To this end particle distributions and total concentrations in terms of number, surface area and mass aerosol metrics were measured at the mainstream side of five different cigarette brands using a condensation particle counter as well as mobility/aerodynamic particle sizers. On the basis of Italian smoking patterns and cigarette consumptions, the excess life cancer risk (ELCR) was then evaluated. Particle concentrations equal to 3-6 x 10(8) part. cm(-3), 60-120 mm(2) cm(-3), and 5-9 g m(-3) for number, surface area and mass metrics, respectively, were measured. Most probable ELCR values ranged from 2 x 10(-1) to 6 x 10(-1) with the higher contribution due to the tobacco-specific nitrosamines and a minor (but still not negligible) contribution of B[a]p, Cd, and As.