| dc.description.abstract | The electrostatic precipitator air-liquid interface (ESP-ALI) exposure systems were recently developed for assessing the toxicity of atmospheric aerosols and air-borne engineered nanomaterials. Generally, the collection efficiency of ESP-ALI was studied for spherical aerosols. However, atmospheric aerosols are not always perfectly spherical and the particle morphology might affect the ESP-ALI collection efficiency as well as the cell toxicity. For instance, the plate-like graphene nanomaterials penetrate into the cell preferred nearly orthogonal and may physically disrupt the cytoskeletal organization of cells. In this study, to explore the effect of particle morphology on the performance of ESP-ALI, three types of monodisperse aerosols, including spherical sucrose particles, non-spherical soot aggregates and silver aggregates/agglomerates, were selected to evaluate the collection efficiency of ESP-ALI at a flow rate ranging from 0.3 to 1.5 LPM. To quantify particle morphology, the fractal dimension (Df) of testing nano-aerosols were characterized using a tandem system of Differential Mobility Analyzer (DMA, TSI 3081) and Aerosol Particle Mass Analyzer (APM, Kanomax 3601). Results show that at identical conditions, the particle penetrations in ESP-ALI decrease with decreasing particle size and increasing applied voltage. The penetration for fine particles (dp= 100-250 nm) under different operating conditions can be well correlated by a characteristic exponential curve using a dimensionless drift velocity (Vc/Vavg,r) as the scaling parameter. It suggests that the performance of the ESP-ALI can be predicted as long as the value of Vc/Vavg,r was known. For UFPs (dp< 100 nm) with different particle morphologies, the particle penetrations in ESP-ALI are similar, but their diffusion losses are not negligible. In contrast, for fine particles, the collection efficiency of soot nano-aggregates (Df= 2.29) is higher than that of spherical sucrose particles. This might be due to the simultaneous influences of the electric-field-induced alignment and the flow-field-induced alignment. Furthermore, based on the Zhibin and Guoquan (1994)’s Deutsch model [1], a quadratic equation was applied to fit the experimental data and be used to predict the performance of the ESP-ALI. | en_US |