Influence of Bifurcation Morphology on Exercise-Induced PAH Deposition in the Lungs: A Computational Modeling Approach for Air Quality Research.

This study examines the influence of lung geometry, physical activity intensity, and aerosol concentration on the deposition efficiencies (DEs) of particulate matter with surface-bound polycyclic aromatic hydrocarbons (PM-PAHs) in human lung generations 3-6. Two-phase flows were effected in ANSYS 2020R2 platform using planar and orthogonal lung geometries, with two levels of physical activities, 4 metabolic equivalents (4 METs), and 8 METs. Aerosol concentrations of 0.95 μg‧m-3, 1.57 μg‧m-3, and 2.04 μg‧m-3 represent rural, urban, and industrial areas, respectively. Relative differences in DEs for 1 μm, 3.2 μm, and 5.6 μm exhibit variations between the two geometries with ranges of 0%-84.4% for 4 METs and 1.2%-50.7% for 8 METs. The first carina region was the most significant hotspot for the 5.6 μm particles. On the other hand, the 1 μm and 3.2 μm aerosols infiltrated and deposited evenly at the lower sections of the lungs. Regarding PM-PAHs doses, spatial variations indicate an industrial > urban > rural hierarchy. This investigation suggests that individuals in industrial and urban locations should manage the intensity of their outdoor activities to minimize exposure to PM-PAHs. These findings are instrumental for public health interventions aimed at reducing exposure to PM-PAHs and preventing associated health problems.