GAS PARTICLE PARTITIONING AND SECONDARY ORGANIC AEROSOL YIELDS/

Secondary organic aerosol (SOA) formation is considered in the framewo rk of the gas/particle partitioning absorption model outlined by Panko w (1, 2). Expressions for the fractional SOA yield (Y) are developed w ithin this framework and shown to be a function of the organic aerosol mass concentration, M(o). These expressions are applied to over 30 in dividual reactive organic gas (ROG) photooxidation smog chamber experi ments. Analysis of the data from these experiments clearly shows that Y is a strong function of M(o) and that secondary organic aerosol form ation is best described by a gas/particle partitioning absorption mode l. In addition to the 30 individual ROG experiments, three experiments were performed with ROG mixtures. The expressions developed for Yin t erms of M(o), used in conjunction with the overall yield data from the individual ROG experiments, are able to account for the M(o) generate d in the ROG mixture experiments. This observation not only suggests t hat SOA yields for individual ROGs are additive but that smog chamber SOA yield data may be confidently extrapolated to the atmosphere in or der to determine the important ambient sources of SOA in the environme nt.