Previous research on multi-component organic mixtures containing up to 10 different compounds has provided interesting data on aerosol hygroscopic growth. For various mixtures of organics, some experiments have indicated continuous growth while other mixtures show restructuring and distinct deliquescence points. Research on super-micron particles has shown a relationship with phase state of the initial particles and deliquescence which may also extent to sub-micron particles and to cloud activity. This has important implications for the comparison of laboratory and field data on aerosol-water interactions and ultimately for understanding the aerosol indirect effect.

In this work, we will present results of experiments measuring hygroscopic growth (using HTDMA), cloud condensation nuclei activity (using CCNC), and phase state/morphology (using AFM) of various mixtures of up to 10 different common organic aerosol components. Additionally, we have analyzed the aerosol generation process typically used in laboratory studies (solution atomization and subsequent drying) to determine what parameters affect the resulting aerosol and its properties. We have investigated the influence of different types of atomizers, solvents, solution concentrations, drying rates and residence times, and temperatures on the resulting particles.

The results indicate that the particular method used to generate aerosols in the laboratory can have an important affect on aerosol morphology and phase state. The resulting aerosol hygroscopic properties are similarly altered with obvious relationships between hygroscopic growth and CCN activity.