Aerosols Of High Chlorine Concentration Transported Into Central And Eastern-United-States

During 18–21 December 1980 a remarkable change occurred in the composition of the aerosol over a broad region of the central and eastern United States: the weight per cent of chlorine present in small aerosol particles increased by nearly two orders of magnitude. We report here an analysis of the aerosol composition and meteorology during the period of change which suggests that this increase was the result not of a pollution episode, but of a massive intrusion of very clean maritime air from the northern Pacific into a region extending at least from Wisconsin southwards to Kansas and Missouri and eastwards to Ohio.