Aerosol characterization by using Mt. Fuji as an observation tower

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East Asia is such a growing industrial region that many kinds of the aerosol and its precursor gas haying different composition are emitted. They display profound temporal and spatial variations due mainly to their relatively short residence time. For the better assessment of climatic impacts, etc., observations on aerosol characteristics (concentration, size distribution, composition, optical property and relations to cloud and fog processes, etc.) in the free troposphere are thus essential. Hence, research on aerosol and its precursor was carried out at Mt. Fuji, an isolated highest peak in Japan (3776m a.s.1.).Three intensified observation campaigns were carried out at the summit (3776m a.s.1.), 7.8 point (3400m a.s.1.) and Tarou-bou (1300m a.s.1.), etc. of the mountain during summers of 2005-2007. It was found that the aerosol and the precursor gas are ruled by local mountain and valley winds, being under a free tropospheric condition during night. The origin of the species found i … More n the upper atmosphere seems different between night and day. Moreover, various continental pollutants could be observed even in summer if the frontal activity creates favorable conditions for the transport. The mountain and valley winds at Mt. Fuji were quantified for the first time by comparing the surface observations by simple equipments on the mountain body with those at the mountain foot and radiosounding. A scale of the developed mixed layer turned out to be, from vertical averaged profile of 0_3 and NO_x by passive samplers, about 2km during summer. Because of few pollution sources, foot of Mt. Fuji including Tarou-bou can serve reference concerning the air pollution of the city. Evaluation of ecosystem response against acid rain and the fog would be possible there. Although the observational data was generalized by a present atmospheric transport model, alternative regional transport model should be used, by which geography of Mt. Fuji is more properly expressed, in the future. Less