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The gas-particle partitioning of select semivolatile organic compounds (SOCs) was studied by injecting the SOCs into a 190 m3 Teflon film chamber containing a secondary organic aerosol (SOA) generated by volatilizing liquid alpha-pinene into an ozone-concentrated atmosphere. The concentration of total suspended particulates (TSP) and gas and particle-phase SOCs was measured over the course of three experiments spanning a temperature range of 268-297 K and a relative humidity range of 55-100%. An equilibrium partition coefficient, Kp, was calculated for each sampling event. Empirical relationships were then developed to predict the partitioning of the SOCs on the SOA particle source as a function of temperature. Partitioning inthis SOA system was compared to that of a SOA generated by the photochemical reaction of NOx with m-xylene. The results indicate that partitioning is similar between the two SOA systems. The effects of multiple particle sources on partitioning was also examined, revealing that a weighted average of predicted Kp, values for individual sources can be used to predict partitioning in aerosol mixtures. [ABSTRACT FROM AUTHOR]