A Model for Lumping Atmospheric Secondary Organic Aerosol and Its Application in Air Quality Modeling

Abstract

This dissertation presents an original theoretical model that lumps the multiple secondary organic aerosol (SOA) components in an organic aerosol mixture into a few lumped compounds, accounting for both temperature and aerosol composition effects on SOA partitioning behavior. The partitioning properties of the lumped groups were derived from those of the individual components. The model was tested and compared with smog chamber experimental data and other theoretical estimates, and was shown to predict the gas-particle partitioning behavior of the overall mixture well. The model was applied to SOA products formed from multiple hydrocarbon precursors to develop a new SOA formulation for application in the Community Multiscale Air Quality (CMAQ) model. The partitioning behavior predicted by the new formulation was compared to experimental data and was shown to be a reasonable approximation.