CCN Properties of Water-soluble Organic Compounds Produced by Common Bioaerosols

Abstract

Polyols are considered mainly to be formed by bioorganisms (fungi) and have been found in large concentrations in atmospheric aerosols in many environments , both in the fine and coarse mode particles. Osmolality and tensiometry measurements were used to calculate the Köhler curves for C 3-C 6 polyols and their analogue di-acids. The results show that the large affinity of polyols with water lowers the Raoult effect of water droplets and leads to similar CCN properties than the corresponding dicarboxylic acids. But because polyols are considerably more soluble than dicarboxylic acids they would activate droplet growth at a much earlier phase. This indicates for the first time that organic compounds produced almost exclusively by bioorganisms could play a role in cloud formation.