Abstract
Since there are strong physical and chemical interactions between gaseous and particulate components in cigarette smoke, it is necessary to clarify their interaction in order to develop an effective removal technique. The present work studied the gas-to-particle conversions in sidestream cigarette smoke by tracing the behavior of key components such as acetaldehyde, isoprene and ethanol. The amount of key components transferred from gas phase to particulate phase was determined from the decrease in gas phase concentration, while the masses of key components trapped in particles were determined by volatilizing these components from the particles into dry clean air for purging. The mass balance between the transferred mass from gas phase to particulate phase and the mass recovered from particles showed that only twenty to thirty percents of these key components were recovered from the particles, suggesting that the transfer mechanisms from gas phase to particulate phase are mostly irreversible. Further, we investigated the formation of particles from cigarette smoke gases, which were obtained by filtering cigarette smoke immediately after burning. Measurements with an optical particle counter showed that high concentration of particles larger than 0.3 μm are newly formed and the nucleation is not suppressed by several times of dilution with clean air. The time scale of nucleation is found to be in the order of ten minutes and the nucleation rate is not affected by the humidity of air. Although the nucleation of gaseous components is intense in the absence of particulate matter, the nucleation has little effect on the overall dynamic behavior of cigarette smoke in the presence of particles.
