MEASUREMENTS OF SPATIAL DISTRIBUTION OF AEROSOLS AND THEIR CHARACTERISTICS BY GROUND-BASED AND AERIAL OBSERVATIONS

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In this research subject, we carried out experiments to analyze the dynamics of aerosols and their precursors in the atmosphere as well as to elucidate the spatial distribution of aerosols and to clarify the chemical transformation processes on the way of long-range transports. For this purpose it is indispensable to analyze the effect of the biggest emission source region, i.e., China. However, the observation experiments over China were thought impossible so far. In this study we could carry out aerial observation experiments of aerosols and air pollutants in China.1.Three times of aerial observations over China were performed in Dec. 2002-Jan. 2003, Aug.-Sept. 2003, and May-June 2004. In the vicinity of a large emission source NOx showed anti-correlation with ozone and high positive correlation with SO_2. NOx/SO_2 ratio was estimated based on those data and the recent phenomena of NOx increase and/or SO_2 decrease were confirmed by comparison with emission inventory data. Sulfates and nitrates showed good correlation with ammonium. Acidic species in aerosols over China were well neutralized with ammonia. From the analysis of organic aerosols, it became clear that there are high concentration of phthalic acid and phthalates in China.2.Continuous ground-based measurements of aerosols and their precursors were carried out in Okinawa. Analyses of transport process and chemical transformation process were made for not only sulfates and nitrates from China but also carbonaceous aerosols transported from South and/or Southeast Asia. It is a remarkable result that the seasonal variation of water soluble organic aerosols was clarified.