Assessment of vapor pressure estimation methods for secondary organic aerosol modeling

Vapor pressure (P-vap) is a fundamental property controlling the gas-particle partitioning of organic species. Therefore this pure substance property is a critical parameter for modeling the formation of secondary organic aerosols (SOA). Structure-property relationships are needed to estimate P-vap because (i) very few experimental data for P-vap are available for semi-volatile organics and (ii) the number of contributors to SOA is extremely large. The Lee and Kesler method, a modified form of the Mackay equation, the Myrdal and Yalkowsky method and the UNIFAC-p(L)(degrees) method are commonly used to estimate P-vap in gas-particle partitioning models. The objectives of this study are (i) to assess the accuracy of these four methods on a large experimental database selected to be representative of SOA contributors and (ii) to compare the estimates provided by the various methods for compounds detected in the aerosol phase. (c) 2005 Elsevier Ltd. All rights reserved.