Effects of Ozone-Mediated Aging on the Oxidative Potential of E-cigarette Aerosols

WONSIK WOO, Alexa Canchola, Michael Lum, Linhui Tian, Ying-Hsuan Lin, University of California, Riverside

     Abstract Number: 256
     Working Group: Health-Related Aerosols

Abstract
The production of e-cigarette aerosols is known to cause the formation of various free radicals and reactive oxygen species (ROS). The oxidative potential and cytotoxicity of fresh e-cigarette aerosols are well-characterized, with previous work showing that the presence of transition metals and oxygen during the formation of e-cigarette aerosols produces the highly reactive OH radical. However, the effects of chemical aging by ambient oxidants in the indoor environment are yet to be elucidated. This brings forward the question of whether the oxidation of organic compounds found in e-cigarette aerosols will lead to a greater formation of ROS and what implications it would have on the health of bystanders. In this study, we aim to determine the effects of ozone on modifying the chemical composition and toxicity of e-cigarette aerosols. E-liquid mixtures will be aerosolized into a 10 m3 Teflon chamber, and the generated aerosols will be subjected to various concentrations of ozone for an hour. The newly formed secondary organic aerosols (SOA), along with fresh aerosols, will be collected to detect the presence of ROS and for cell exposures to determine cytotoxicity. The presence of radical species will be determined by electron paramagnetic resonance (EPR) spin-trapping, and their relative abundance will be quantified with the DCFH2DA assay. Cell exposures to various concentrations of fresh e-cigarette aerosols and their SOAs, along with a lactate dehydrogenase (LDH) assay, will be used to measure relative cytotoxicity. Through the aging process, we expect to see a greater amount of ROS formation in chemically aged e-cigarette aerosols than that found in fresh e-cigarette aerosols. Given that the toxicological characteristics of e-cigarettes are mainly associated with the inhalation of fresh aerosols in current studies, our work may provide a perspective that characterizes second- and third-hand vaping exposure as a significant health risk.