Abstract
Rain samples were collected sequentially (each about 1mm) through rain events on 9-10 June, 27 August, and 19 October 1989 at Nagatsuta campus, Tokyo Institute of Technology. The concentrations of F- and Br- ions ranged from 0.20 to 53.8μg/l and from 0.74 to 19.0μg/l in three rain events, respectively. The ratios of F-/Cl- were high at the initial stage and gradually decreased. There was a high correlation between concentrations of Ca2+ and F- in three rain events, whose coefficient was 0.97, 0.89, 0.99 for rain events on 9-10 June, 27 August, and 19 October, respectively. On the other hand, the ratios of Br-/Cl- were approximately equal to the sea salt ratio (3.4×10-3). However, in rain events on 9-10 June and 19 October, the ratios of Br/C1- largely exceeded sea salt ratio at the middle or final stages of the events. There was a high correlation between N03- and non-sea salt Br- indicating that anthropogenic Br- was loaded on precipitation.
