微观水滴表面张力降低的明显证据
The ability of airborne particles to take up water may beenhanced by surface-active components, but the importanceof this effect is controversial because direct measurement ofthe surface tension of microscopic droplets has not been possible.Here we infer droplet surface tension from wateruptake measurements of mixed organic-inorganic particlesat relative humidities just below saturation (99.3–99.9%).The surface tension of droplets formed on particles composedof NaCl and a-pinene ozonolysis products wasreduced by 50–75%, but only when enough organic materialwas present to form a film on the droplet surface at least0.8 nm thick. This study suggests that if atmospheric particlesare predominantly (?80%) composed of surface-activematerial, their influence on cloud properties and thus climatecould be enhanced, and their atmospheric lifetimes could bereduced. Citation: Ruehl, C. R., P. Y. Chuang, A. Nenes, C. D.Cappa, K. R. Kolesar, and A. H. Goldstein (2012), Strong evidenceof surface tension reduction in microscopic aqueous droplets,