Source profile and excess cancer risk evaluation of environmental tobacco smoking under real conditions, China

Abstract

To demonstrate the chemical characteristics and carcinogenic risk of environmental tobacco smoke (ETS) emission, replicate PM2.5 samples were collected via volunteers smoking nine different brands of Chinese cigarettes. The source profile of ETS was established with an abundance of inorganic and organic chemical compositions, source signatures were recognized, and a comparison of excess cancer risk of heavy metals versus polycyclic aromatic hydrocarbons (PAHs) was completed. The results showed that organic carbon (OC), element carbon (EC) and potassium (K) were the primary components in the ETS profile; chromium (Cr), lead (Pb) and cadmium (Cd) were the most abundant heavy metals; and PAHs were mainly distributed in middle molecular weight (MMW) and high molecular weight (HMW) ranges. Benz(a)anthracene (BaA), benzo(b)fluoranthene (BbF) and chrysene (CHR) could distinguish ETS from cooking/outdoor stationary sources as source-related markers. The ranking of excess cancer risk of heavy metals was Cr > Cd > arsenic (As) > Pb > nickel (Ni) and that of PAHs was benzo(a)pyrene (BaP) > BaA > BbF > indeno(1,2,3-cd)pyrene (IND) > CHR. The comparison revealed that the totality of excess cancer risk of heavy metals was 785 times higher than that of PAHs, indicating that the harmful health effect caused by inorganic compositions during ETS exposure should attract public attention.