10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Reactive Oxygen Species Generation by Particle Size-dependent Transition Metal Ions using a Kinetic Multi-layer Model in the Epithelial Lining Fluid
TING FANG, Pascale Lakey, Rodney J. Weber, Manabu Shiraiwa, University of California, Irvine
Abstract Number: 928 Working Group: Aerosols and Health - Connecting the Dots
Abstract Soluble transition metal ions (e.g. Fe and Cu) in particulate matter (PM) are critical aerosol species to generate reactive oxygen species (ROS) upon deposition in human respiratory lining fluid by redox cycling, Fenton, and Fenton-like reactions, leading to oxidative stress and adverse health effects. Quantifying ROS generation in respiratory system is important in understanding the health effects of particulate metals, but direct measurements of ROS in respiratory tract is so far not available. The kinetic multi-layer model of surface and bulk chemistry in the epithelial lining fluid (KM-SUB-ELF) [1] has been developed to estimate the amount of ROS generated within the ELF by simulating the reactions of transition metal ions with antioxidants. Particle sizes affect the location and amount of ambient soluble transition metal ions deposited in the respiratory system and thus affects the ROS generation. In this study, ambient size distribution of water-soluble transition metal ions were obtained by analyzing MOUDI (Micro-Orifice Uniform Deposit Impactor) samples collected from a road-side and representative urban site in Atlanta, GA. Deposition of transition metal ions in the ELF were then estimated using an empirical expressions derived from human inhalation data (ICRP) [2,3]. The KM-SUB-ELF model was then applied to the deposition data to estimate the size-dependent ROS generated in the ELF by transition metal ions in the nasal cavity, bronchi, and alveoli. We summarize and compare the ROS generation due to transition metal ions in different segments of human respiratory tract and compare to the reference level between healthy human and those with respiratory diseases.
References: [1] Lakey et al., Sci. Rep., 2016. [2] Fang et al., ES&T, 2017. [3] ICRP. Human Respiratory Tract Model for Radiological Protection, 1994.