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Casari, Matthew John

Electrical Engineering

2012

MS

As studies of particulate matter are used to predict air quality and determine links between particulate size and health effects, size-discriminated monitoring of engine exhaust particulate has been studied largely using laboratory instruments. However, the relative size, power consumption, and cost of these instruments makes them impractical for routine on-board (i.e., in-situ) measurements of tailpipe emissions. Having large in-situ data sets from a variety of vehicles operating under real-world conditions wi11lead to improved accuracy of particulate emissions modeling for local and natIonal forecasting. Such data could be collected by the development, of low-cost, low-power, small-footprint particle sizing instrumentation that can withstand the rigorous conditions associated with real-world, on-board exhaust sampling of many vehicles.
This work describes contribution towards the development of the Portable Ultrafine Particle Sizer (PUPS). The PUPS is a compact (size) instrument specifically designed to be incorporated on a vehicle to monitor engine exhaust particle in the ultrafine range (<100 nano-meters in diameter). Fundamentals of the PUPS are based on an Electrical Aerosol Spectrometer (EAS), consisting of a corona ionizer for particle charging, a reverse Differential Mobility Analyzer (rDMA) for particulate size-discrimination, and electrometer detectors for particle concentration measurements. Utilizing primarily commercial off-the-shelf electronic technologies and modern components such as Flexible Printed Circuit Boards, miniature diaphragm air pumps, and integrated circuit electrometers, the prototype PUPS system has been developed and tested at a fraction of the cost of a laboratory-based instrument. The complete system design and integration, as well as characterization of the electrometers and the rDMA system have been the focus of this research.