AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Accurate Control of Relative Humidity for HTDMA Particle Growth Rate Measurements
STEVEN CEVAER, Suresh Dhaniyala, Clarkson University
Abstract Number: 364 Working Group: Instrumentation and Methods
Abstract Research on the interaction of aerosol particles with water vapor is important to determine particle lifetime, light scattering properties, and role in cloud formation. The hygroscopic tandem differential mobility analyzer (HTDMA) is an instrument commonly used to measure growth rate and deliquescence of particles as a function of relative humidity (RH). Particle growth rate measurements with the HTDMA can be used to determine particle compositions and to help differentiate the constituents of an externally mixed sample. Accurate particle size response to RH can only be achieved with an accurately controlled humidification process for the scanning DMA’s sheath and aerosol flows. For particle sources that vary in space or time, it is also necessary that the RH control system quickly stabilize at desired RH values. We studied several humidification systems and evaluated their response times and ability to maintain long-term humidity control. The results of this study will be presented and implications for fast HTDMA measurements will be discussed.