AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Towards Fast, Accurate Calculation of Particle Hygroscopic Growth Rates: System Modeling of H-TDMA Performance
RAGHAV RAMAN, Suresh Dhaniyala, Clarkson University
Abstract Number: 215 Working Group: Instrumentation and Methods
Abstract The response of particles to humidity in the environment directly influences its lifetime, interaction with sunlight, and ability to form clouds. Measurement of change in particle size as a function of humidity is typically made using a hygroscopic tandem differential mobility analyzer (HTDMA). The effectiveness of particle growth measurements with a HTDMA is dependent upon the time response and precision of the instrument. In this study, a HTDMA software emulator is developed to model the instrument response considering scanning diffusional DMA transfer functions, multiple charging of particles, and statistics of the sampled aerosol. The emulator is used to determine the minimum HTDMA measurement time required for accurate growth measurements to determine the nature of the external mixture. The performance of the emulator is tested against HTDMA measurements made under laboratory conditions for different aerosol types. The development of the emulator, HTDMA instrument, and analysis of the experimental results will be presented and implication for fast HTDMA measurements, such as necessary from aircraft platforms, will be discussed.