Parent, Alkylated, and Sulfur/Oxygen-Containing Polycyclic Aromatic Hydrocarbons in Mainstream Smoke from 13 Brands of Chinese Cigarettes

China has the world's largest population of smokers with serious health consequences, yet we know a very limited spectrum of hazardous chemicals in cigarette smoke even for carcinogenic polycyclic aromatic hydrocarbons (PAHs). Here, we chose 13 popular cigarette brands sold in China markets, collected particulate matters in mainstream smoke using filter pads and an automatic smoking machine, and analyzed 56 PAHs, including 31 parent, 18 alkylated, and 7 sulfur/oxygen-containing PAHs (S/O PAHs). The 56 PAHs in mainstream smoke totaled from 244.2 ± 28.5 to 10254.8 ± 481.5 ng cig–1; parent, alkylated, and S/O PAHs shared 16–23%, 64–74%, and 6–18%, respectively. Benzo[a]pyrene (BaP) ranged 1.1–41.6 ng cig–1, while BaP equivalent concentrations (BaPeq) ranged 3.6–120.2 ng cig–1, but contributions to BaPeq by individual carcinogenic PAH species varied with cigarette brands. When these cigarette smoke source profiles were pooled together with those of other combustion ones available in the literature, we found that widely used diagnostic ratios of parent PAHs failed to distinguish cigarette smoke from other combustion sources, except that the ratio indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene + benzo[g,h,i]perylene) can largely separate cigarette smoke from vehicular emissions and that the ratio of Retene/(Retene + chrysene) can further discriminate cigarette smoke from coal combustion when alkylated PAHs are involved.