AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Design and Collection Efficiency of A New Electrostatic Capillary Collector For Fine and Ultrafine Particulate Matter
GAURAV MAHAMUNI, Byron Ockerman, Igor Novosselov, University of Washington
Abstract Number: 708 Working Group: Instrumentation and Methods
Abstract Collection of fine and ultrafine particulate matter is used for monitoring exposure to potentially harmful particles: aeroallergens, toxins, emissions from combustion sources that can contribute to cardiovascular and respiratory diseases. We introduce a novel Electrostatic Capillary Collector (ECC) that collects aerosol in the range below 2.5 micron directly onto the outer surface of a capillary that can be used for in-situ analysis. The ECC uses a ring and concentric needle configuration as ionizer to charge particles as they enter the collector. The particles then pass through an electric field between a cylinder and a concentric wire inserted into the bore of the capillary, and are collected on the outer surface of the capillary wall. The capillary is 4 inch long and has an outer diameter of 350 micron. Real time particle sizers (TSI SMPS and APS) are used to maximize the collection efficiency(CE) on the capillary substrate. The sampling flow rates are varied from 1 L/min to 3 L/min. For a specific flow rate, voltage applied across the needle - ring ionizer (corona voltage) and the wire - cylinder (repelling voltage) are optimized. Additionally, CE is measured for the optimized operating conditions using bulk fluorescence method. Collection of fluorescent particles in the size range of 0.2 to 2 micron is done on the capillary and on a reference filter for mono-dispersed particles in aerosol chamber. At the flow rate of 2L/min, typical collection efficiency for particles smaller than 2 micron is higher than 50%. Transparent nature of the capillary collection substrate can be used to obtain spectroscopic signatures of collected sample, in-situ.