Assessment of dioxin and dioxin-like compounds in mainstream smoke from selected US cigarette brands and reference cigarettes.

Mainstream cigarette smoke (MSS) from 12 US cigarette brands and two reference cigarettes was evaluated to determine concentrations of dioxins (i.e., polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs)). The study included three 'tar' ranges based on Federal Trade Commission (FTC) determination: Low Yield (LY) < or = 5.5, Medium Yield (MY) 9.6-12.2, and High Yield (HY)> or = 14.5 mg/cig. Of the brands studied, the HY cigarettes yielded the greatest mean concentrations of 2005 World Health Organization Toxic Equivalents (WHO-TEQs) on a per cigarette basis. WHO-TEQ levels in LY cigarettes were significantly lower than for HY cigarettes (p=0.039) on a yield per cigarette basis and WHO-TEQ concentrations correlated with 'tar' yield (r=0.73, p=0.007), as did concentration on a WHO-TEQ per body mass per day basis (r=0.73, p=0.007). However, a statistically significant relationship was not observed between 'tar' yield levels and WHO-TEQ concentrations on a per mg Total Particulate Matter (TPM) basis. Concentrations for all brands tested ranged from 0.44 to 3.88 fg WHO-TEQ/mg TPM. Maximum daily exposure estimates calculated from this range (0.004-0.074 pg WHO-TEQ/kg bw/day) are below the current WHO Tolerable Daily Intake range of 1-5 pg/kg bw/day.