Effects of Aerosol Particles on Atmospheric Environment

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Atmospheric aerosols play an important role in environmental problem. To evaluate the effects of aerosol on atmospheric environment, the three works : (1) Physical and chemical characteristics of atmospheric aerosols, (2) Global warming/cooling effects of atmospheric aerosols, (3) Mechanism of acid rain/acid deposition, were carried out during 1997-1999.1. Characteristics of atmospheric aerosolsPhysical and chemical properties were investigated under the various meteorological and environmental conditions. The particle size distribution of mass was expressed always as a bimodal distribution that was divided into fine and coarse fraction at around 1-2μm. The size distribution of each chemical component was classified into three types : single modal distribution within either fine or coarse fraction and the bimodal one as well as total mass. Water solubility of aerosols depended strongly upon their elemental components. Although Fe, Si and Ti showed high insolubility, almost whole of S a … More nd Cl dissolved.2. Global warming/cooling effects of atmospheric aerosolsThe simultaneous measurements of aerosol properties and radiation were performed as the campaign experiments at ground in 1998 and at both ground and aircraft in 2000, as well as the routine measurement. The radiative forcing was calculated from radiation and aerosol data. The average radiative forcing in Kyoto and Nagoya were -1.5 and +3.3W/mィイD12ィエD1, respectively. The difference in their values originates in the difference of chemical composition, i.e. optical property of aerosols.3. Mechanisms of acid rain/acid depositionThe sampling method and treatment procedures to fix fog-and rain-droplets were investigated and the elemental analysis of the fixed single particle was tried applying PIXE and micro-PIXE analyses. Liquid particles were easily fixed by either exposing to cyanoacrylate vapor or freezing method. The elemental concentrations in single raindrop were obtained as a function of raindrop diameter. The concentrations in raindrop were extremely high at the begging of rain. Less