Effect of Sorption on Exposures to Organic Gases from Environmental Tobacco Smoke (ets)

The effects of sorption processes on dynamic ETS organic gas concentrations and potential exposures were studied in a carpeted and furnished 50-m room ventilated at 0.6 h. Ten cigarettes were machine-smoked on six of every seven days over four weeks. Concentrations of ETS-specific tracers and regulated toxic compounds were quantified during daily smoking, post-smoking and background periods. Potential exposures were calculated by period and day. Large sorption effects were observed for the widely used tracers 3-ethenylpyridine and nicotine, and for several toxic compounds including naphthalene and cresol isomers. Shortterm adsorption to indoor surfaces reduced concentrations and potential exposures during smoking, while later reemission increased concentrations and exposures hours after smoking ended. Concentrations during nonsmoking periods rose from day to day over the first few weeks, presumably from increased reemission associated with increased sorbed mass concentrations. For sorbing compounds, more than half of daily potential exposures occurred during nonsmoking periods. INDEX TERMS Environmental tobacco smoke, Pollutant sorption and desorption, Exposure assessment, VOCs and SVOCs, Laboratory and field experiments INTRODUCTION Environmental tobacco smoke (ETS) is a dynamic mixture of particles, inorganic compounds, and organic gases that span a wide volatility range. The ETS gas-phase (filtered ETS) has been identified as carcinogenic in animal-based toxicology studies (Witschi et al., 1997). Many individual ETS organic gases are regulated as toxic air contaminants and hazardous air pollutants (henceforth referred to as “toxic compounds”) by the California state and United States federal governments, respectively (CARB, 2001). Quantifying exposures to toxic organic gases in ETS is challenging since many of these compounds are also emitted from other sources. One approach is to measure exposure to a tracer compound that is specific to ETS. Exposure to ETS toxic components then may be estimated based on the relative abundances of toxic and tracer compounds as measured in ETS under controlled conditions. This approach requires that tracer and toxic compounds exhibit similar dynamic behavior (Daisey, 1999). Nicotine and its primary metabolite cotinine are the most widely used chemical tracers of ETS exposure. Yet it has been known for some time that nicotine dynamics differ from those of other ETS components (Eatough, 1993). In light of this concern, other gas-phase tracers have been suggested, including 3-ethenylpyridine (3-EP), pyridine, and pyrrole (Eatough, 1993; Hodgson et al., 1996). * Contact author email: [email protected] Proceedings: Indoor Air 2002