Particle and inhalation exposure in human and monkey computational airway models

Area of Science:

• Pulmonary Medicine
• Toxicology
• Biomedical Engineering

Background:

• Regional deposition of inhaled aerosols is critical for assessing health risks.
• Upper airway physiology filters particles, with inertial impaction dominant for micrometer particles.
• Monkeys serve as human surrogates in inhalation toxicity studies due to anatomical similarities.

Purpose of the Study:

• Predict particle deposition (1-10 µm) in monkey and human upper airway models across various inspiratory flow rates.
• Investigate differences in inhalation flow and particle deposition between humans and monkeys.
• Validate numerical simulations with in-vitro and in-vivo data.

Main Methods:

• Computational modeling of human and monkey upper airway anatomy.
• Simulation of aerosol particle transport and deposition under varying flow rates.
• Comparison of numerical results with experimental data (in-vitro and in-vivo).

Main Results:

• Monkey airway models showed good agreement with in-vitro and human data when using equivalent Stokes numbers.
• Predicted vestibule removal efficiencies were higher in the monkey model than the human model.
• Particle transport sensitivity was observed concerning anatomical structure, airway geometry, airflow, boundary conditions, and particle size.

Conclusions:

• Numerical simulations provide essential insights into inhaled particle deposition in monkey airways.
• Differences in deposition patterns, particularly in the vestibule, exist between human and monkey models.
• Accurate prediction of particle distribution in monkeys is vital for human health risk extrapolation.