Calculated SHS emissions from one person-hour of waterpipe and cigarette smoking. Cigarette smoker is assumed to consume two full-flavored cigarettes per hour and is based on human subject measurements of SHS by Bi et al. (2005). Theoretical waterpipe range corresponds to the smoker exhaling none or all of the inhaled toxicant. “Best estimate” assumes toxicant fractions exhaled as previously reported (Baker and Dixon, 2006) for cigarette smokers. Reported totals for PAH and aldehydes correspond to compounds shown in Table 1, excluding dibenz[a,h]-anthracene and methacrolein, respectively, for commensurability with Bi et al., 2005.