Experimental and Numerical Smoke Carcinogen Deposition in a Multi-Generation Human Replica Tracheobronchial Model

Abstract

A better understanding of submicron particle deposition in the respiratory tract is needed to study the health effects caused by carcinogenic particles. Recent studies indicate that random diffusion is not sufficient to describe the motion of these particles in complex geometries, rendering conventional models inaccurate. A solid replica of excised human lung segments was used to create digital and hollow models of the tracheobronchial region to investigate deposition of mainstream (MS) and sidestream (SS) cigarette smoke particles. Particle sizes for the carcinogen Benzo(a)pyrene (BaP) in SS smoke, and total particulate matter (UVPM) in SS and MS smoke were measured and used to compare the simulation to experimental data. Excellent agreement was found between predicted and measured results. Random diffusion was not found to be significant for submicron particles indicating that particles were instead transported to the airway wall by convective diffusion. BaP in SS smoke was an average 0.3 µm compared to 0.36 µm for UVPM in SS smoke. The trends in both experimental and numerical results indicated that the BaP in SS smoke deposits at a slightly higher efficiency than the UVPM, indicating that carcinogen-specific deposition, rather than total particulate matter should be considered when investigating health effects.

Computational investigation of particle inertia effects on submicron aerosol deposition in the respiratory tract

“…These computational studies employ either a Eulerian-Lagrangian (Balashazy, Hofmann, & Heistracher, 2003;Hofmann, Golser, & Balashazy, 2003;Moskal & Gradon, 2002;Robinson, Oldham, Clinkenbeard, & Rai, 2006) or a Eulerian-Eulerian (Ingham, 1975(Ingham, , 1991Lee & Lee, 2002;Martonen, Zhang, & Yang, 1996;Shi, Kleinstreuer, Zhang, & Kim, 2004;Zhang, Kleinstreuer, Donohue, & Kim, 2005) model for submicron particle transport and deposition. The Lagrangian transport model tracks individual particles within the Eulerian flow field and can account for a variety of forces on the particle including inertia, diffusion, gravity effects, and near-wall interactions (Longest, Kleinstreuer, & Buchanan, 2004).…”

Aerosol Dosimetry Modeling Using Computational Fluid Dynamics

“…A realistic head airway geometry was generated by Sosnowski et al [16,17] from computed tomography (CT) and magnetic resonance imaging (MRI) images, in which the influence of realistic breathing patterns on the deposition was measured for various particle sizes. Experiments on cigarette smoke deposition have also been performed on a human replica of the tracheobronchial airways generated from CT scans [18].…”

“…These imaging techniques have been extensively used to generate realistic representations of the respiratory tract. For example, replicas and computational geometries of tracheobronchial airways have been developed based on CT images [18,96,97], and MRI images were the basis for the realistic geometries of the oropharyngeal airways generated in refs. [98,99].…”

Characterization of particle deposition in a lung model using an individual path

“…Particles were introduced by means of an injection type called surface, specifying particle properties and velocity. Robinson [11] founded that 50,000 particles are necessary to minimize random variation in the deposition efficiency predictions due to the randomness of the particle position profile.…”