Environntent International, VoL 15, pp. 5 7 - 64, 1989 0160-4120189$3.00 +.00 Printed in the U.S.A. All rights reserved. Copyright 01989 Pergamon Press plc SIDESTREAM TOBACCO SMOKE CONSTITUENTS IN INDOOR AIR MODELLED IN AN EXPERIMENTAL CHAMBER- POLYCYCLIC AROMATIC HYDROCARBONS Trinh Vu-Duc and Cong-Khanh Huynh Institute of Medicine and Occupational Hygiene, University of Lausanne CH-1005 Lausanne, Switzerland E1 87-626 (Received4 November 2987; Accepted 4 April 2989) Exposure to sidcstream tobacco smoke is concerned with constituents in suspension in the indoor atmosphere. The natural dissipation of sidestream tobacco smoke has been investigated in a static atmosphere in a I0 m3 experimental chamber, and the rate of dissipation is expressed as T0.s, the half-life of residence in the air. Respective T0j of smoke components are calculated from the various sample data points, assuming a kinetic equation of the first-order process. Sidestream smoke has been generated by a smoking machine according to the Coresta standard protocol and then left to age over an 8-hour period, with subsequent sampling at defined time intervals. The experiments have been repeated over five days, and eight data point samples are obtained for each experiment. Besides nicotine, CO, and smoke particulate matter, interest has been focused on polycyclic aromatic hydrocarbons (PAH). The initial concentrations, Co for smoke particulate matter and nicotine (gas and particulate phases) are found to be 13.8 mg and 92 J4g per cigarette per cubic meter, with T0.s being 2.6 and 2.1 hours, respectively. Low-molecular-weight PAH have T0.s up to 20 hours, explainable only by their high concentrations in the gas phase, while the 3- to 7-ring PAH have T0.s of about 2 hours. The contribution of CO to ambient concentration is 91 mg per cigarette per cubic meter. The data can be useful in mathematical modvllization studies regarding ventilation or exposure to sidestream smoke. INTRODUCTION With regard to the emission levels of pollutants and the various nature and number of chemical sub- stances in the smoke, tobacco smoke is, along with other combustion appliances, one of the predominant sources of air pollution in indoor atmosphere (NAS 1981). The incomplete pyrolysis of cigarette tobacco generates elevated concentrations of air contaminants (IARC 1986). Moreover, the smoke that is released into the ambient atmosphere between puff-drawing is known to contain higher amounts of pollutants than that inhaled by the smoker (Brunnemann et al. 1980; Klus and Kuhn 1982; Neurath and Ehmke 1964; Sakuma et al. 1984). In comparison, the emissions from other 57 indoor sources appear overlapped in the presence of tobacco smoke (Girman et al. 1982; Good et al. 1982), with the exception of the emissions by the combus- tion of fossil fuels from gas appliances, kerosene burners, space heaters, or wood burning likely to be used indoors (Spengler and Cohen 1985). The degree of pollution, and therefore the degree of health risk to occupants, depends on the type and the amount of pollutants entering the occupied space and the rate of removal by processes such as deposition, chemical reactions, and mechanical ventilation. Passive smoking is related to the exposure to in- door air contaminated by smoke components in the gaseous and particulate phases. The major source of