AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Development of an Aerosol Concentrator/Diffusion Battery Tandem for Evaluating the Toxicological Properties of Concentrated Ambient Accumulation Mode Particles in Controlled Inhalation (In-vivo) Exposure Studies
MILAD PIRHADI, Amirhosein Mousavi, Sina Taghvaee, Mohammad Sowlat, Constantinos Sioutas, University of Southern California
Abstract Number: 23 Working Group: Instrumentation and Methods
Abstract The ability to conduct exposures using the concentrated ambient accumulation mode particles separately from ultrafine particles (UFPs) has been a serious challenge in the health studies. In this study, we were able to overcome this major limitation in exposure studies by designing and evaluating the performance of a tandem technology, consisting of the developed versatile aerosol concentration enrichment system (VACES) and a screen-type diffusion battery, which removes ambient UFPs from the airflow, enabling us to directly conduct exposure studies on concentrated ambient accumulation mode particles (0.18-2.5 μm). First, we evaluated the performance of the diffusion battery using various types of laboratory-generated aerosols under controlled conditions. The optimum operational flow rate (5 lpm) and number of stages (6 stages) of the diffusion battery was selected based on the lab tests. We subsequently deployed the diffusion battery in our sampling site in the Los Angeles, and connected it to the VACES in order to evaluate the VACES/diffusion battery performance using the ambient fine particulate matter (PM2.5). The field tests results confirmed the capability of the tandem technology to concentrate efficiently the ambient accumulation mode PM while the majority of the UFPs are removed from the concentrated aerosol. The diffusion battery illustrated a 50% cut-point of around 100 nm, and the removal efficiency of particles less than 50 nm exceeded 70–90%. The mass concentrations and chemical composition of the ambient accumulation mode particles collected using the tandem technology compared with those collected with a reference sampler, MOUDI, in parallel vary around 5-15%. This excellent agreement further corroborates the high efficiency of the VACES/diffusion battery tandem technology to directly conduct exposure studies on concentrated ambient accumulation mode PM.