Polonium in size fractionated mainstream cigarette smoke, predicted deposition and associated internal radiation dose. (October 2016) - Tiwari, M.
Abstract: In this study, size fractionated mass and 210 Po activity concentrations in mainstream cigarette smoke (MCS) were monitored for three popular cigarette brands. Size segregated collection of MCS was carried out using a cascade type impactor, while mass and 210 Po activity concentration were analyzed gravimetrically and alpha spectrometry (following the radiochemical separation) respectively. Multiple-Path Particle Dosimetry (MPPD V2.11) model is used for prediction of deposition fraction calculations for the MCS deposition in different compartment of human respiratory tract. The activity concentration of 210 Po is founds 10.56 ± 2.46 mBq per cigarette for the tested cigarette brands. 210 Po size distribution indicates most of this associates with fine fraction (Dp < 2.23 μm) of cigarette smoke. The committed annual effective dose to smokers (smoking on an average 20 cigarette a day), considering the 210 Po and 210 Pb concentrations (assuming it is in secular equilibrium with 210 Po) in MCS, was estimated between 0.22 and 0.40 mSv, with mean value of 0.30 mSv for tested cigarette brands. Considering the risk factor of fatal cancer due to radiation exposure of lung (exposure time of 30 years); the average collective estimated fatal cancer risk is estimated as 1.5 × 10 −4 due to 210 Po and 210 Pb exposure to smokers. Highlights: Mass and 210 Po size distributions were estimated for mainstream cigarette smoke. 210 Po in MCS was found to be associate with fine fraction (dp < 2.23 μm). Size dependent deposition fractions were used for MCS for 210 Po exposure to smoker. Average annual effective dose of 0.30 mSv to a regular smoker due to 210 Po/ 210 Pb.