Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, California 91125, United States.
Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
Environ Sci Technol. 2018 Feb 20;52(4):2134-2142. doi: 10.1021/acs.est.7b05575. Epub 2018 Feb 9.
Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a unified theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor-wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry conditions.
二次有机气溶胶（SOA）的形成在实验室室内进行研究，其中挥发性有机化合物（VOCs）被氧化产生低挥发性化合物，这些化合物凝结到气溶胶相中。已经证实，这种氧化的低挥发性化合物可以分配到腔室壁中，腔室壁传统上由特氟隆薄膜制成。有几项研究测量了个别蒸气化合物向腔室壁的吸收速率，但缺乏能够描述一系列实验测量的统一理论。在这里，提出了一种观察到的特氟隆壁环境室中短和长蒸气-壁相互作用时间尺度的两层模型，并证明与超过 90 种化合物的壁沉积速率的实验数据一致。从模型中的关键参数与蒸气分子特性之间导出了半经验关系，可用于预测在干燥条件下腔室内气相蒸气的命运。
