Doses and lung burdens of environmental tobacco smoke constituents in nonsmoking workplaces

This paper models nicotine dose and ultraviolet-absorbing particulate matte r (UVPM) alveolar lung burden resulting from exposure to environmental toba cco smoke (ETS) for nonsmokers in workplaces where smoking was reported not to occur. Data were obtained from personal monitoring of ETS in 16 U.S. ci ties [Jenkins R.A., Guerin M.R., Palausky A., Counts R.W., Bayne C.K., and Dindal A.B. Determination of human exposure to environmental tobacco smoke (ETS): a study conducted in 16 U.S, cities. Draft final report by Oak Ridge National Laboratory for Center for Indoor Air Research, Linthicum, MD, 199 6a; Jenkins R.A., Palausky A., Counts R.W., Bayne C.K., Dindal A.B., and Gu erin M.R. Exposure to environmental tobacco smoke in sixteen cities in thee United States as determined by personal breathing zone air sampling. J. Ex pos. Anal. Environ. Epidemiol. 1996b: 6(4): 473 -502.]. This is a continuat ion of earlier analyses focusing on nonsmokers in smoking workplaces (SWs) [LaKind J.S., Graves C.G., Ginevan M.E., Jenkins R.A., Naiman D.Q., and Tar diff R.G. Exposure to environmental tobacco smoke in the workplace and the impact of away - from - work exposure. Risk Anal. 1999a: 19 (3): 349-358; L aKind J.S., Jenkins R.A., Naiman D.Q., Ginevan M.E., Graves C.G., and Tardi ff R.G. Use of environmental tobacco smoke constituents as markers for expo sure. Risk Anal. 1999b: 19(3): 359-373; LaKind J.S., Ginevan M.E., Naiman D .Q., James A.C., Jenkins R.A., Dourson M.L., Felter S.P., Graves C.G., and Tardiff R.G. Distribution of exposure concentrations and doses for constitu ents of environmental tobacco smoke. Risk Anal. 1999c: 19(3) : 375-390.]. E ven though study participants characterized their workplaces as nonsmoking, some individuals reported observing cigarettes in the workplace. Individua ls observing six or more cigarettes were excluded from the analysis on the grounds that they were in de facto SWs. Exposure to ETS was lower in nonsmo king than SWs, but even with this exclusion, exposure was not zero. Distrib utions were selected for each model input, and at least 2000 iterations of the model were made for each dose or lung burden characterization (e.g., fo r females, for males). In these nonsmoking workplaces (NSWs), neither nicot ine nor UVPM concentrations were lognormally distributed. Hence, observed c oncentrations were used directly via bootstrap sampling (nicotine) or a con stant number of times (UVPM) as input to the models. As in SWs, individuals from smoking homes (SHs) experienced greater exposure in NSWs to both nico tine and UVPM than did individuals from nonsmoking homes (NSH; P<0.001). Th e distributions of modeled nicotine dose and UVPM lung burden were highly s kewed, with most individuals receiving relatively low exposure to ETS in th e workplace. Comparing doses from NSWs modeled here to doses from SWs model ed previously, less difference between smoking and NSWs was apparent in UVP M levels than in nicotine levels. For average exposure, UVPM alveolar lung burdens were approximately 10-fold higher in smoking than NSWs, while avera ge nicotine doses were 20-25 times higher in smoking than NSWs. These findi ngs are in the range observed by other investigators and are partly explain ed by very low denominators in the ratios (i.e., very low levels experience d in NSWs). For upper bound exposure, the nonsmoking-to-smoking ratios rema ined about the same for UVPM. For nicotine, the upper bound ratios remained the same for people from NSHs but were halved for people from SHs.