American Association for Aerosol Research - Abstract Submission

AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA

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Towards a Miniature, Tippable, Water Condensation Particle Counter

SUSANNE HERING, Gregory Lewis, Steven Spielman, Aerosol Dynamics Inc.

     Abstract Number: 492
     Working Group: Instrumentation and Methods

Abstract
Using the three stage growth concept coupled with a continuous wick, we have developed a laminar-flow, water-based condensation particle counting method that is potentially small and portable. Our prototype instrument can be operated in any orientation, as there are no water reservoirs. It runs for several days without addition of water. The continuous wick spans three temperature regions, the middle one of which is warmer than the other two. Water evaporation from the warmed, middle section provides the water vapor that creates the supersaturation for particle activation and growth. This water vapor is recovered by the cooler, downstream section of the wick and transported back to the warmed mid-section via capillary action. This approach has been demonstrated successfully for sampling both dry and humid air. We have attained four days of continuous operation, without addition of water, for typical room conditions, ie 30-70% RH at 20-25°C. Measured particle number concentrations are within 10% of those from a bench-top WCPC. This approach should be miniaturizable, with potential as a wearable instrument for ultrafine particle number concentration monitoring.