(682b) Aerosol Production From Solution Atomization and the Important Influences of Solvent, Concentration, Solution Age and Chemistry

Solution atomization and subsequent drying is the primary method by which aerosols are generated for laboratory studies such as CCN activity, hygroscopic growth, or smog chamber seeding experiments. The typical assumptions for this atomization process include:

1) The solvent does not affect the aerosol properties

2) The concentration of solution only affects the size distribution

3) The solution produces the same aerosols regardless of its age

4) The solution contains chemicals that do not react in any way

We have conducted experiments using both organic and inorganic compounds and mixtures dissolved in a variety of solvents. We have investigated CCN activity and particle morphology of the resulting atomized particles after increasing aging of the solution. While Koehler theory accurately describes the activation of soluble inorganic salts, it is still not possible to accurately predict the water interaction behavior of organic aerosols. In recent years, several studies of CCN activity for organic aerosols have investigated the effects of solvents, organic coatings, mixed particles, and smog chamber-generated aerosols. The results of these studies are not in agreement and have resulted in conflicting findings. The current study has used a commercially available cloud chamber (DMT CCNC) and the recently reported Scanning Mobility CCN Activity (SMCA) method to measure several different organic species and mixtures of varying complexity.

Additionally, we have investigated the morphology for atmospherically-relevant sized particles using Atomic Force Microscopy (AFM). Results have been analyzed to determine the relationships among chemistry, solvent, aging, and concentration. We have discovered that particle morphology may vary depending on the particle generation methods and conditions and that the morphology may influence properties such as CCN activity.