Mathematical Modeling of Cigarette Smoke Particles Dynamics in High Air Change Rate Chambers like Cars

Dynamics of cigarette smoke particles in high air change rate chambers like cars is investigated and the RSP concentration during and after smoking the cigarette is predicted in this study. This model is based on the mass balance equation. The generation and removal rate of RSP for various particle sizes are specified from the cigarette emission profile, ventilation rate, filtration efficiency, coagulation of particles and deposition rate on surfaces. The cigarette emission profile serves as the main source term in the mass balance equation. Ventilation rate and filtration of the cabin are considered as sinks for emitted particles due to the cigarette smoking in cars. These effects together with the mechanism of deposition on the interior surfaces are the main sinks for cigarette smoke particles in high surface-to-volume ratio chambers like cars. The coagulation is taken into account as a sink for smaller particles and as a source for larger particles. The conducted experiments on the PM2.5 concentration level after smoking the cigarettes in cars are summarized and the smoking scenarios of the reported experiments are simulated in this study. In most of experimental studies in cars, the total PM2.5 concentration is measured and reported, thus, the predicted concentration of each size section is integrated over the all range of particle sizes up to 2.5 μm to obtain a value comparable with the total PM2.5 concentrations in the literature. Good agreement between the results of the present model and the experimental data is reached. The results of the current model are also compared with the presented mathematical model in the literature on the RSP concentration in cars (e.g. USEPA Indoor Air Quality Model). The similar trend of RSP concentration are observed between the results of the different models and the minor quantitative discrepancies are most likely due to different cigarette particle emission rate being incorporated in the various models. 13 Annual & 2 International Fluid Dynamics Conference FD2010 26-28 Oct. Shiraz University Shiraz Iran