Radon and daughters in cigarette smoke measured with SSNTD and corresponding committed equivalent dose to respiratory tract

Uranium (U-238) and Thorium (Th-232) contents were measured inside various tobacco samples by using a method based on determining detection efficiencies of the CR-39 and LR-115 II solid state nuclear track detectors (SSNTD) for the emitted alpha particles. Alpha and beta activities per unit volume, due to radon (Rn-222), thoron (Rn-220) and their decay products, were evaluated inside cigarette smokes of tobacco samples studied. Annual committed equivalent doses due to short-lived radon decay products from the inhalation of various cigarette smokes were determined in the thoracic and extrathoracic regions of the respiratory tract. Three types of cigarettes made in Morocco of black tobacco show higher annual committed equivalent doses in the extrathoracic and-thoracic regions of the respiratory tract than the other studied cigarettes (except one type of cigarettes made in France of yellow tobacco); their corresponding annual committed equivalent dose ratios are larger than 1.8. Measured annual committed equivalent doses ranged from 1.8 x 10(-9) to 1.10 x 10(-3) Sv yr(-1) in the extrathoracic region and from 1.3 x 10(-10) to 7.6 x 10(-6) Sv yr(-1) in the thoracic region of the respiratory tract for a smoker consuming 20 cigarettes a day. (C) 2002 Elsevier Science Ltd. All rights reserved.