An Investigation of the Size-Supersaturation Relationship of Soluble Condensation Nuclei

Abstract

The activation supersaturation of several artifically prepared NaCl aerosols was measured in the laboratory using a thermal gradient diffusion chamber. Size distributions of these aerosols and total particulate concentrations were determined with a Whitby Aerosol Analyzer and a Gardner Small Particle Detector. From a combination of these data, the relationship was derived between supersaturation and necessary minimum size of the particles for nucleation. This experimentally obtained correlation indicates that, at a given supersaturation, a NaCl particle, has to be two to three times larger than theory predicts in order to be active as a cloud condensation nucleus. Possible explanations for the discrepancy are discussed.