AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Temperature Dependence of Vapor Wall Deposition: A Case Study with Levoglucosan
ADITYA KIRAN SRIKAKULAPU, Vikram Pratap, Qijing Bian, Jeffrey R. Pierce, Philip K Hopke, Shunsuke Nakao, Clarkson University
Abstract Number: 562 Working Group: Aerosol Chemistry
Abstract Recent studies have shown that wall deposition of semi-volatile organics significantly affects the interpretation of smog chamber experiments. None of the previous studies, however, focused on low temperature conditions that may be relevant to wintertime atmosphere. Temperature is expected to significantly affect vapor wall deposition primarily through reduction in saturation pressure. In this study, we investigated the role of temperature in vapor wall loss in a Teflon chamber over a wide temperature range including sub-zero °C for the first time. We used levoglucosan as an example semivolatile molecular marker to investigate vapor wall loss in an outdoor 6 m3 Teflon smog chamber located in Potsdam, NY. The outdoor set up allowed us to perform chamber experiments in warm conditions in summer and cold conditions in winter. Preliminary analysis of aerosol size distribution data based on an aerosol microphysics model showed that under warm temperatures, the majority of levoglucosan resided in the wall, whereas under sub-zero °C, levoglucosan vapor wall loss was negligible due to kinetically limited evaporation from the particle phase. This study confirmed the key role of saturation pressure in vapor wall loss within a Teflon chamber.