Gas/particle partitioning and yield levels of polycyclic aromatic hydrocarbons and n-alkanes in the mainstream cigarette smoke of commercial cigarette brands

The gas/particle partitioning of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes was investigated in the mainstream smoke (MSS) from 59 commercial cigarette brands classified according to the existence of filter tip, the tar yield indicated on the packet, and the cigarette length and diameter, into 15 cigarette classes: non filter (NF), high (H), medium (M), light (L), super light (SL), ultra light (UL), one-tar yield (O), 100-mm long (H-100, L-100, SL-100, UL-100, O-100), and slim (SL-SLIM, UL-SLIM, O-SLIM). The gas/particle partitioning constant, Kp, was determined and its relationship with the subcooled liquid vapour pressure pL° of individual compounds was investigated. A good linear relationship was obtained for both chemical classes following the equation log Kp = mr log pL° + br. In all cigarette classes, PAHs were found to sorb more strongly on MSS particles than n-alkanes. Carcinogenic PAHs were detectable only in the total particulate matter (TPM) of MSS and their yields increased linearly with the TPM yield. However, when normalized against TPM, the yields of carcinogenic PAHs were quite similar in all cigarette classes with a slight drop from low tar- to high tar-yield brands suggesting probably lower biological activity per mg TPM for the latter. The nicotine-normalized PAH yields were also similar among the different cigarette classes suggesting that, if smokers adjust their smoking behavior to achieve a consistent nicotine intake, they will be exposed to an equivalent amount of carcinogenic PAHs regardless of whether they smoke full-flavored, light, or ultralight varieties.