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

Abstract

This paper models nicotine dose and ultraviolet-absorbing particulate matter (UVPM) alveolar lung burden resulting from exposure to environmental tobacco 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. cities [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, 1996a; Jenkins R.A., Palausky A., Counts R.W., Bayne C.K., Dindal A.B., and Guerin M.R. Exposure to environmental tobacco smoke in sixteen cities in the United States as determined by personal breathing zone air sampling. J. Expos. Anal. Environ. Epidemiol. 1996b: 6(4): 473–502.]. This is a continuation 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 Tardiff 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; LaKind J.S., Jenkins R.A., Naiman D.Q., Ginevan M.E., Graves C.G., and Tardiff R.G. Use of environmental tobacco smoke constituents as markers for exposure. 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 constituents of environmental tobacco smoke. Risk Anal. 1999c: 19(3): 375–390.]. Even though study participants characterized their workplaces as nonsmoking, some individuals reported observing cigarettes in the workplace. Individuals 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 nonsmoking than SWs, but even with this exclusion, exposure was not zero. Distributions 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., for females, for males). In these nonsmoking workplaces (NSWs), neither nicotine nor UVPM concentrations were lognormally distributed. Hence, observed concentrations were used directly via bootstrap sampling (nicotine) or a constant number of times (UVPM) as input to the models. As in SWs, individuals from smoking homes (SHs) experienced greater exposure in NSWs to both nicotine and UVPM than did individuals from nonsmoking homes (NSH; P<0.001). The distributions of modeled nicotine dose and UVPM lung burden were highly skewed, with most individuals receiving relatively low exposure to ETS in the workplace. Comparing doses from NSWs modeled here to doses from SWs modeled previously, less difference between smoking and NSWs was apparent in UVPM levels than in nicotine levels. For average exposure, UVPM alveolar lung burdens were approximately 10-fold higher in smoking than NSWs, while average nicotine doses were 20–25 times higher in smoking than NSWs. These findings are in the range observed by other investigators and are partly explained by very low denominators in the ratios (i.e., very low levels experienced in NSWs). For upper bound exposure, the nonsmoking-to-smoking ratios remained 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.