Tracheobronchial and alveolar particle surface area doses in smokers

Cigarette smoke is the main cause of lung cancer events. Mainstream cigarette smoke (MSS) is a direct concern for smokers, but also the secondhand smoke (SHS) contributes to the smoker exposure. In addition, smoker exposure is affected by the "free-smoke" particle exposure (B), related to the micro-environments where smokers spend time. The aim of this paper is to evaluate the daily alveolar and tracheobronchial deposited fractions of airborne particles for smokers as the sum of these three contributions: MSS, SHS, and B. Measurements of particle surface area distributions in the MSS were performed through a Scanning Mobility Particle Sizer, an Aerodynamic Particle Sizer, and a Thermo-dilution system on five types of conventional cigarettes. A Monte Carlo method was then applied to evaluate the most probable value of dose received during the inhalation of MSS by smokers. Measurements of particle concentrations in SHS and at the "free-smoke" particle background (B) were performed through 24-h monitoring at a personal scale of adult smoker through hand-held devices. This paper found that the total daily deposited dose for typical smokers was 1.03 × 105 mm2 · day-1. The main contribution of such a huge daily dose was addressable to the MSS (98%) while SHS contributed 1.1%, increasing up to 2% for people smoking only while traveling in a car.