AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Design and Development of a Self-Contained Personal Electrostatic Bioaerosol Sampler (PEBS)
TAEWON HAN, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 26 Working Group: Bioaerosols
Abstract The goal of this project is to develop a personal electrostatic bioaerosol sampler (PEBS). PEBS is a two-stage electrostatic precipitator consisting of a novel wire-to-wire charger and a dual half-cylinder collection chamber. The newly designed wire-to-wire charger produces very low ozone concentrations (only ~ 10ppb) compared to more traditional charger designs, such as wire-to-cylinder or wire-to-plate. This new charging concept allows maintaining desirable physiological characteristics of collected bioaerosols during a long-term sampling process, leading to a more accurate sample analysis. When PEBS is operated, aerosols (and bioaerosols) are drawn into an open channel collector, electrically charged by the wire-to-wire charger and deposited onto a removable stainless steel plate. A one-inch long tungsten wire (0.003 inches in diameter) is positioned in the center of the charging chamber (i.e., 1-inch cylinder) and connected to the high voltage; and a ring of stainless steel wire (0.015 inches in diameter) is surrounding the “hot” electrode at its midpoint and is grounded.
At this stage of development, the sampler was tested in the laboratory at different charging and sampling voltages when challenged with polystyrene (PSL) particles ranging from 0.025 nm to 3 µm in diameter and at flow rates of 10 L/min and 30 L/min. Investigated sampling times ranged from 10 min to 4 hours. The sampler’s collection efficiency was determined by measuring the amount of particles deposited on the collection plate relative to the particle concentration upstream of the sampler. For the investigated particles, including the nano-sized ones, the collection efficiency was 70-90% at charging voltages of (+)5.5 kV, while collection voltage was set to (-)7 kV. Overall, PEBS showed very consistent collection efficiency (~70%) even after 4 hours of continuous operation. The use of the unique wire-to-wire charger resulted in ozone production below 10 ppb. Experiments with bioaerosol also show high collection efficiency.