Modeling Age-Related Particle Deposition in Humans

Inhalation of airborne material poses a potential health risk to various subpopulations one of which is children. Little is known about the fate of particles in the respiratory tracts of children. Modeling efforts have been limited due largely to the lack of adequate information on lung geometry during growth. Lung morphometry measurements in children and adults between 3 months and 21 years of age were used to create 5-lobe lung geometries. Each lobe had a dichotomous, symmetric branching structure and was structurally different from the other lobes. The lung geometries were used in a multiple-path particle deposition model to calculate particle deposition fractions in different regions, lobes and airway generations of the lungs. Simulated breathing patterns were representative of resting breathing. Age-dependent, semi-empirical expressions of particles losses in the nasal airways, which were based on fits to the available experimental measurements, showed larger nasal deposition in adults than in childr...