Dissolution behavior and surface tension effects of organic compounds in nucleating cloud droplets

Solubilities and surface tensions were measured for difunctional organic acids in various concentrations of (NH 4 ) 2 SO 4 and NH 4 HSO 4 aqueous solutions. Model results using these data indicate that the organic compounds affect cloud droplet growth by two mechanisms: by gradual dissolution in the growing droplet which affects the shape of the Köhler growth curve, and by lowering of surface tension which decreases the critical supersaturation.