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When Aerosol Science Meets the Respiratory Tract: An Update for Inhaled Particle Modeling
ROBERT PHALEN, Mark Hoover, Roger McClellan, University of California Irvine
Abstract Number: 277
Working Group: Health-Related Aerosols
Abstract
Inhaled aerosol particle deposition models are important for designing inhaled medications, estimating risks from air pollutants, and understanding respiratory tract biology and diseases. Following the seminal publication of W. Findeisen that applied four deposition mechanisms to smooth solid spherical particles passing through a simplified airway structure, a large number of improved inhaled aerosol deposition models have emerged. Improvements, driven by practical needs, involved introducing more-complex aerosols, new deposition mechanisms, more-complete and detailed airway models, and new exposure scenarios. Although the new models have improved medical treatments, risk assessments, and our basic understanding of the respiratory tract, additional improvements are needed.
Advances in aerosol physics have allowed for adding many particle types to models, including fibers, agglomerates, nano-sized, charged, volatile and semi-volatile, liquid, high- and low density, and biological. Also, environmental scenarios, such as altered gravitational and magnetic forces, temperature and humidity extremes, and highly-concentrated aerosol systems are becoming better understood.
Anatomy and physiology data are essential inputs to inhalation models. These change according to age, gender, ethnicity, disease state, species, exertion level, aerosol exposure history and environmental conditions, to name a few. These factors are being added to the deposition models as data become available, but what is unknown exceeds what is known. This hampers applying aerosol deposition calculations to individuals and new exposure scenarios.
A recent multi-disciplinary international conference in Irvine, CA produced research-related recommendations for improving inhaled aerosol deposition modeling. These recommendations included improvements in the aerosol science, anatomy, physiology, and other aspects of the models as well as the need for new collaborations, focusing on health-related applications, establishing data repositories, and attracting new talent to the field.