AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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A Variable Residence Hygroscopicity Tandem Differential Mobility Analyzer (VRHTDMA)
DEANNA MYERS, James Smith, Jonathan Abbatt, University of California, Irvine
Abstract Number: 537 Working Group: Instrumentation and Methods
Abstract Because atmospheric aerosol particles can grow into cloud condensation nuclei, it is crucial to understand how size-selected particles uptake water and the timescale of that process in order to predict their potential climate impacts. In addition, quantifying the timescale and magnitude of water uptake in particles provides insight into particle morphology and phase state, which are important considerations for determining heterogeneous chemical processes. To address these needs, we have developed a Variable Residence Hygroscopicity Tandem Differential Mobility Analyzer (VRHTDMA) to measure the hygroscopicity of aerosol nanoparticles and to provide insights into the timescales of water vapor uptake. The VRHTDMA is a standard HTDMA that can determine hygroscopic growth factors and kappa as functions of dry diameter. In addition, this instrument contains four different humidification channels that allow the particles to experience humidification times of 2, 4, 10 and 58 seconds. Results from laboratory characterization experiments are presented. In addition, we present measurements obtained by the VRHTDMA from the OASIS campaign in Utqiagvik, Alaska that demonstrate instrument performance.