Characterization of Sources and Sinks of the Oxidative Potential of Particulate Matter Emitted from Household Sources
P. S. GANESH SUBRAMANIAN, Brent Stephens, Mohammad Heidarinejad, Vishal Verma, University of Illinois Urbana-Champaign
Abstract Number: 189
Working Group: Health-Related Aerosols
Abstract
Oxidative potential (OP) is a metric, which quantifies the ability of particulate matter (PM) to induce oxidative stress in humans and is used as a surrogate metric to estimate PM toxicity. Although people spend over 80% of their time indoors, literature on OP of PM emitted from indoor sources is limited. In this study, we plan to collect PM emitted from common household sources (unscented-candles, incenses, cigarettes, ultrasonic humidifiers, essential oil diffusers, toasters, and air fryers) using a clean-controlled-environmental-chamber and develop an OP emission inventory from these sources to characterize the sources and sinks of OP of indoor PM in typical US homes. We will collect time-resolved PM samples (i.e., 10-12 samples/source during each emission experiment) either using a manifold filter holder configuration or using a mist chamber (MC) to directly collect PM in liquid (water-suspension). The MC will be connected to a programmable syringe pump and multi-position valve to enable semi-automated multi-sample collection. The particle number concentrations (PNC) in the chamber will also be quantified at 2-min time-intervals using a combination of scanning mobility particle sizer (SMPS) and optical particle sizer (OPS) in tandem. The OP of PM collected on the filters/water-suspension will be analyzed using three widely used acellular OP assays; dithiothreitol depletion (OPDTT), glutathione depletion (OPGSH), and hydroxyl radical generation (OPOH). The time-resolved OP and PNC data would be analyzed using a well-mixed mass balance model approach to estimate the individual mechanistic source and sink parameters that govern the physicochemical processes of indoor OP and PM. We anticipate the outcome of this approach to provide us the emission rates (EOP and EPNC) and first-order loss rates (kOP and kPNC) of OP and PNC, which would assist in further our understanding on the evolution and dynamics of indoor generated PM and its health effects.