Gas/particle partitioning theory for secondary organic aerosol

Abstract

The paper reviews the gas/particle partitioning theory for secondray organic aerosol formation and describes its development and possible applications. In atmosphere, semi-volatile organic compounds are formed through oxidation of certain gas-phase organic species and the secondray organic aerosol formation may be best described by a gas/ particle partitioning absorption model. The process of gas/particle partitioning is dependent on both the composition, concentration and vapor pressure of semi-volatile species, and the concentration and composition of absorptive materials. On the basis of gas/particle partitioning theory, the thermodynamic model for gas/particle partitioning of molecular constituents has also been developed. This model can be used to predict the liquid water contents in aerosol, distributions of inorganic compounds and hydrophilic/hydrophobic organic compounds. The combination of the chemistry mechanism and the thermodynamic model for secondary organic aerosol formation with the California Institute of Technology (CIT)'s three-dimensional urban/regional atmospheric model could be used to perform comprehensive gas- and aerosol- phase simulations.