Simulation of cigarette smoke dynamics in denuder tubes considering particle phase chemistry
The aerosol dynamics model ADiC was extended to include chemical reactions. It is used to computationally replicate denuder tube experiments where freshly generated cigarette smoke is drawn through a vertically arranged, acid covered tube to capture alkaline substances. The calculated deposition rates and total deposition are compared to experimental findings from several studies that investigated respective quantities for nicotine (and ammonia). Further, the form of deposition, vaporous and condensed phase, is considered. The model does not apply any parameters changing physico-chemical properties to fit simulation and experimental findings.
The only variable parameter used in all simulations is the choice of the amount of acid initially in the system to establish a certain pH value. An initial pH of 5.9 to 6.25 (i.e. the baseline scenarios) allows for replicating the nicotine deposition rate and total deposition in the lower tube sections. For the same simulation, ammonia deposition rate and total deposition are of the order of the experimental data. For the simulation featuring the initially lower pH value, the deposition of ammonia is lower than the experimental data – in the other case it is higher. Increasing the molality of alkaline substances initially in the system by roughly 20% drastically reduces the differences between simulated and measured nicotine deposition rate.
The present model describes some aspects of the dynamics of the complex cigarette smoke in a simplified manner; however, since it is independent of experiment specific parameters it may be applied to other environments such as deposition in the respiratory tract.