Gas/Particle Partitioning and Secondary Organic Aerosol Yields

Abstract

Secondary organic aerosol (SOA) formation is considered in the framework of the gas/particle partitioning absorption model outlined by Pankow. Expressions for the fractional SOA yield (Y) are developed within this framework and shown to be a function of the organic aerosol mass concentration, Mₒ. These expressions are applied to over 30 individual reactive organic gas (ROG) photooxidation smog chamber experiments. Analysis of the data from these experiments clearly shows that Y is a strong function of Mₒ and that secondary organic aerosol formation is best described by a gas/particle partitioning absorption model. In addition to the 30 individual ROG experiments, three experiments were performed with ROG mixtures. The expressions developed for Y in terms of Mₒ, used in conjunction with the overall yield data from the individual ROG experiments, are able to account for the Mₒ generated in the ROG mixture experiments. This observation not only suggests that SOA yields for individual ROGs are additive but that smog chamber SOA yield data may be confidently extrapolated to the atmosphere in order to determine the important ambient sources of SOA in the environment.