Toxic Particles Deposition in the Human Respiratory Tract under Natural Inspiratory Flow

Abstract

Toxic particle (PM2.5) deposition in the human respiratory tract is investigated under natural inspiratory flow. The flow physics of nostrils is asymmetric, and its effect on particle deposition needs prompt attention. An ideal 3-D CT-scan-based geometrical model of the human respiratory tract is re-constructed from the nasal cavity to the 7th generation bronchi. The pulsatile numerical simulation is performed with light (10 L/min) and moderate (40 L/min) inspiratory flow. The Lagrangian method is adopted to compute particle deposition fraction (DPF) in the airways. The suspended particle mass of 300 µg/m3 (poor air quality) (dp = 2.5 µm in diameter) is released from the inlet of airways at every time interval (∆t). The results revealed that the pattern of particle transportation is not similar in both the bronchus and particle hot spots are constituted in the airways. Findings guide optimal targeted drug delivery and the assessment of ventilation illness under hazardous exposure in distinct populations.