American Association for Aerosol Research - Abstract Submission

AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA

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Losses of Cigarette Smoke Particles in Oral Cavities

Bahman Asgharian, OWEN PRICE, Jeff Schroeter, Colin Dickens, John McAughey, Applied Research Associates, Inc.

     Abstract Number: 132
     Working Group: Health Related Aerosols

Abstract
Accurate prediction of the dose of inhaled cigarette smoke particles to the lungs is directly affected by losses in oral cavities. Coagulation and condensational growth of cigarette smoke particles during the puffing and subsequent mouth-hold may result in appreciable losses in the oral cavities by sedimentation. Recent measurements of particle deposition in the oral cavities have indicated a higher fraction of losses than computational predictions due to gravitational settling during the initial mouth-hold of the puff. Visualization of the cigarette puff suction into the oral cavities demonstrated a strong free shear flow initiating through the lips, travelling through the oral cavities, hitting the back of the mouth, and finally mixing with the initial air residing in the mouth. Additional deposition of cigarette smoke particles on the back of the mouth is feasible if particles gain adequate inertia during the puff. To investigate the significance of impaction losses, idealized flow calculations were conducted where the flow in the oral cavities was assumed to be uniform at the lips but developed axially during the travel in the mouth. The flow then impinged on a flat surface, representing the back of the mouth. The axial and tangential components of the flow profile were used in particle transport equations to calculate particle trajectories and deposition on the impaction plate. Model predictions showed small losses that varied with the suction flow rate and initial size of particles. Together with losses during the subsequent mouth-hold, the total loss of cigarette smoke particles can be described by impaction and sedimentation in oral cavities. This study was funded by British American Tobacco.