Narrow Results

The study of single raindrops is expected to give new and great information such as drop formation processes and pollutant scavenging mechanisms. To investigate the characteristics of individual raindrops, PIXE method was applied to elemental analysis. Size-segregated individual raindrops were collected at Kyoto University during rain event in October 2001. Detection limit of each element for polycarbonate filter used as the substrate of raindrops was calculated. The significant peaks of several elements in single raindrop corresponding to the channel number of PIXE could be resolved. Chlorine, potassium, and sulphur were found as major elements in each size raindrop. Strong raindrop size-dependence of every elemental concentration was shown. Chlorine, chromium, potassium, and calcium show the distinctively high scavenging rate at the beginning rainfall. They show 98 %, 97 %, 96 %, and 84 % scavenging rate, respectively and followed by iron and sulphur.