AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
The Gap between Short and Long Timescales in Vapor-Wall Interaction in Laboratory Chambers
YUANLONG HUANG, Ran Zhao, Sophia Charan, Christopher Kenseth, John Seinfeld, California Institute of Technology
Abstract Number: 149 Working Group: Aerosol Chemistry
Abstract Vapor wall deposition can play a significant role in lowering secondary organic aerosol yields in environmental chamber studies. Two key mass transport steps control the vapor-wall interaction in chamber studies: bulk phase boundary layer diffusion and interfacial vapor accommodation. Recent studies reveal conflicting conclusions about the rate-limiting step in vapor wall uptake. The discrepancy arises from several possible aspects: 1. “memory effects” from sampling lines and the instrumental inlet; 2. the chemical system itself; and 3. unresolved vapor-polymer film interaction mechanisms. In this study, the “memory effect” is examined experimentally and is interpreted theoretically by an adsorption model. Wall deposition of in situ oxidation products in both low- and high- NOx environments are investigated under a range of relative humidities to assess the effect of differing chemical systems on wall deposition. A two-stage sorption model is proposed to explain short and long vapor-wall interaction timescales.