Calculated cancer risks for polycyclic aromatic hydrocarbon mixtures in mainstream smoke of cigarettes sold in China

Abstract

China is the world's largest consumer of cigarettes. However, the potential cancer risk posed by polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke, especially species other than benzo[a]pyrene (BaP) remains unclear. In this study, we collected yield data on multiple PAH species from a variety of cigarettes in the China market and calculated their smoking-related incremental lifetime cancer risk (ILCR) values. The computed ILCRs of the total PAHs (ILCRΣPAHs) for ≥95% of the brands were one order of magnitude higher than the acceptable level. ILCRBaP accounted for only 5.0%–37.7% of ILCRΣPAHs among brands, indicating that using single analyte BaP to represent ΣPAHs would significantly underestimate ILCRΣPAHs. No clear trend of changes in ILCRΣPAHs was found for Chinese cigarettes over multiple years, suggesting that smoking cessation is still the best option to minimize the cancer risk of PAHs. The comparison study showed that rarely reported PAHs from Chinese cigarettes can contribute over half of ILCRΣPAHs for several American cigarettes, highlighting the imperativeness to improve the diversity of analytes for Chinese cigarettes. Adults would need to inhale the air-borne PAHs with a BaP equivalent concentration of at least 53.1 ng/m3 to reach the ILCR value comparable to that obtained from smoking.