What to do with NOECS/NOELS-prohibition or innovation?

Abstract

This study attempted to be as realistic as possible when evaluating third-hand PAH residues resulting from 1 cigarette. Smokers were not asked to change their smoking habits, except to continuously hold the cigarette in 1 hand during the entire duration of the cigarette’s burning. Hand size (that is, the adsorptive surface area), duration of smoking, and environmental conditions such as wind, temperature, and humidity, in addition to other factors, may potentially influence PAH concentration. We conducted our third-hand smoke studies outdoors under environmental conditions, and therefore hypothesize that a similar study conducted in the more stable conditions of an indoor environment may reveal higher levels of contaminant residues on surfaces and smokers’ bodies. Moir et al. (2008) quantified PAH concentrations in second-hand tobacco smoke, defined as environmental tobacco smoke that is inhaled involuntarily or passively by someone who is not smoking. Using their study and our data set, we carried out a ‘‘back of the envelope’’ calculation to estimate the percentage of sidestream smoke (i.e., secondhand smoke) that becomes third-hand smoke. We conclude that the PAH inventory on 1 hand of a smoker represents 0.1% to 6% of that emitted from sidestream smoke. Third-hand PAH residues on a smoker’s hand represent only a fraction of the total PAH reservoir for a smoker (compared to residues on all exposed skin and clothing). We have begun to quantify this load of chemicals as the first step in assessing the potential for smokers to act as vectors for impairment of indoor air quality. To completely capture the health risk posed by third-hand smoke, further studies from our research group and others need to address the off-gassing or desorption potential of these compounds and more fully evaluate the significance of third-hand smoke residues in impairing indoor air quality and/or increasing PAH exposure to subpopulations such as children. A thorough ranking of the importance of this exposure route compared to other exposures modes (e.g., release of PAHs from cooking methods such as open fires, incense burning, indoor tobacco smoking, etc.) also remain to be quantified.