Abstract
The composition of the larger (> 10−12 g) hygroscopic particles in the atmosphere was investigated, with use of a phase-transition method. Particles were collected on stretched spider webs exposed from an aircraft, and samples were taken in both maritime and continental air in different meteorological and geographical situations. It was found that the great majority of hygroscopic particles was composed of sea salt, sometimes in combination with insoluble material. A chemical test on individual particles indicated that no appreciable decrease in chloride content or replacement of chlorides by carbonates took place. Only occasionally were large soluble particles, other than sea salt, detected.
