In vitro measurement and dynamic modeling-based approaches for deposition risk assessment of inhaled aerosols in human respiratory system

Abstract

Respiratory deposition dynamics of inhaled particle are developed rapidly in recent decades. Understandings of aerosol properties are useful for predicting respiratory deposition risk. This study conducted an aerosol exposure experiment to quantify the respiratory deposition dynamics of inhaled aerosols, and to infer the deposition risk probability. The experimental aerosols included reference oil droplets and road dust particles. This study developed an aerosol dynamic model to simulate time-dependent particle concentration in exposure chamber and respiratory system. The parameters of particle loss in exposure chamber and deposition in respiratory system can be estimated by experimental measurements. The deposition risks were estimated through particle size distributions and size-dependent deposition fractions. We showed that the experimental and predicted deposition fractions were consistent with the previous in vivo, in vitro and in silico studies. We found that the generated aerosols were polydisperse that followed a lognormal distribution with geometric mean diameters of 0.52 and 0.26 μm for resuspended oil droplet and road dust, respectively. The deposition rate estimates range from 0.015 to 0.362 and 0.013 to 0.157 s−1 in particle size ranging from 0.3 to 3.0 and 0.3 to 4.0 μm for oil droplet and road dust, respectively. Result also revealed that inhaled oil droplet had higher respiratory deposition risk than road dust aerosol. Our study has major implications for the respiratory tract burden of inhaled fine particles from long-term exposure in ambient air based on our developed probabilistic risk model.