Simulation of Particle Deposition in Respiratory Tracts of School-Age Children using Multiple-Path Particle Dosimetry Model (MPPD)

School children are exposed to a number of airborne contaminants that pose a health risk. While many studies focused on indoor and outdoor particle concentrations in school classrooms and outdoor air, few studies have examined the particle deposition in the respiratory tract of school children. In this study, the objective is to simulate and assess the deposition fraction of particles in the lung airways of school-age children, 5 to 18 years old. Particle concentration had been collected for school cabins and school classrooms in the Los Angeles area. This data will be employed as input of the MPPD model for the calculation of particle deposition and clearance. Geometrical parameters, including functional residual capacity and upper respiratory tract volume; various particle properties; and exposure conditions, including breathing frequency and tidal volume are input for estimating inhaled particle deposition. Deposition is calculated from input to theoretical equations for particle deposition efficiency. Results will show the regional deposition fraction and lobar fraction in the respiratory tract under different exposure scenarios and at different ages. It is hypothesized that the highest deposition fraction happens in small size range and there is an increase in deposition in the respiratory tract with decrease in age. Younger children, therefore, are at higher health risks when exposed to particles. Further investigation is needed to study the deposition and the associated health risks.