Health risks associated with cigarette sidestream smoke inhalation

[[abstract]]Cigarette sidestream smoke particulate matter (CSSP) is a common source of indoor air pollutants for nonsmokers. We measure the contents of metals and polycyclic aromatic hydrocarbons (PAHs) in CSSP emitted from Long Life cigarettes, a leading brand in Taiwan. 29 metals and 17 PAHs are found in CSSP. CSSP-bound metals may increase the chance of developing cancer by 9.27~20.93 x 10-6 and the hazard quotient for non-cancer toxicity by 0.496~0.286 when a Long Life cigarette is smoked in a 60-m3 poorly ventilated room. In contrast to Western cigarettes, cadmium is the primary toxic metal present in Long Life CSSP and accounts for more than 90% and 80% of metal-associated cancer and non-cancer risk, respectively. PAHs that are carcinogenic and probably carcinogenic to human comprise about one fifth of the total PAH mass. Carcinogenic potency is equivalent to 144 ng benzo[a]pyrene (BaP) per cigarette. When smoking occurs in a 60-m3 room, CSSP-bound PAHs increase cancer risk by a 1.44 x 10-6 chance per cigarette. In addition, the concentration of PAHs in the room is equivalent to 2.4 x 10-6 mg/m3 BaP, which is above the reference concentration for developmental toxicity recommended by US Environmental Protection Agency. High concentrations of CSSP are cytotoxic. Elevation of AhR expression in lung cells can attenuate CSSP-induced ROS generation and cytotoxicity. However, metals and PAHs are not the causes for cytotoxicity and have no effect on AhR activity