AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
A Hi-Volume Dichot Sampler to Collect Fine and Coarse Particulate Matter for Chemical Composition
Guan Zhao, Philip K. Hopke, Paul A. Solomon, SURESH DHANIYALA, Clarkson University
Abstract Number: 193 Working Group: Instrumentation and Methods
Abstract Accurate sampling and measurement of size-classified particulate mass is necessary from a regulatory perspective and also for studies on health effects of ambient aerosol. For sensitive and high-resolution composition measurements, instruments sampling large volumetic flowrates are required. A high volumetric (hi-vol) instrument was investigated for sampling PM$_(2.5), and PM$_(10-2.5). For sampling fine (PM$_(2.5)) and coarse (PM$_(10-2.5)) particles, different single-nozzle high flow dichotomous sampler designs were numerically and experimentally analyzed. To establish the role of turbulent dispersion on particle separation characteristics of a virtual impactor, the performance of hi-volume VIs was experimentally established as a function of Reynolds number. A new design criterion for hi-vol dichotomous samplers operating in turbulent regime was established.
For complete compositional characterization, particles must be collected on a range of substrate types. For particle capture downstream of the VI on multiple substrates, a plenum-based flow-splitter is designed to trifurcate the sample flow and collect particles uniformly on three open-face filters. Numerical modeling results are used to optimize the design of the collector section, minimizing particle loss in the section. The integrated collector-VI setup is evaluated experimentally in the laboratory. The development of this sampler will enable a near-complete mass balance of the coarse and fine fractions of the collected particles and will be suitable for use in monitoring networks for coarse particle chemical speciation and highly useful for PM-related health effects research.