Green tuff probes were exposed at summits in Tanzawa mountains for half a year in 1993-1994 and wereanalyzed accumulated acid components (nitrogen oxides and sulfur oxides) on the surface of the probe by means of laser microprobe mass spectrometry. The relative heights of mass fragment peaks of NO₃^-, NO₂^-, NO^-, SO₃^- and S0₂^- against that of HSiO₃^- (m/z=77) were compared.
1) Two accumulation patterns were observed between the western sites and the eastern sites. 2) Several tens percent of the accumulates were found at the sites on the mountains (ca. 1600 m) against the reference site, Ohyama Shimosha (700m) which provides observation data on total ion deposites and gas phase acid measurements. 3) The accumulation at the south side of summits where birch trees have been destroyed, were significantly lower than those at the north side, where birch trees are alive.
The proposed method can be utilized as a simplified semiquantitative method for monitoring the effects of acid components against soil better than the methods using copper plates and marble stone.

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The dispersion of secondary pollutants and volcanic SO₂ over the Kyushu area during a spring-time high pressure system was analyzed based on comprehensive observational data. The clockwise air circulation within the high pressure system trapped the air pollutants which resulted in both long-range transport from the Asian continent to Japan and local transport of domestic pollutants. Airplane and surface observations show narrowly peaked SO₂ concentration from Mt. Sakurajima volcano during conditions when Kyushu is located at the western boundary of the high pressure system. At the same time, high O₃ concentration exceeding 80 ppb were observed over most of Japan (especially the western part). O₃ concentration and specific humidity were inversely correlated which indicates strong intrusion of stratospheric O₃ into the lower troposphere. The data analysis revealed that the photochemical 0₃ production due to the anthropogenic NO_X emission was about 10-20%. HNO₃, nitrate and aldhyde were high concentrations when high local production of O₃ was observed.
Conversion rates from SO₂ to SO₄^2-were determined based on surface observation data trajectory analysis and revealed values of about 2.5%/hour.
The present study shows that dispersion pattern of pollutants over Kyushu are very complicated when spring-time high pressure conditions prevailed. The long-range transport from both the mainlad Asia and Japan, as well as volcanic SO₂ plume transport and stratospheric 0₃ intrusion into the lower troposphere combine to be responsible for the observed high concentration of secondary pollutants.

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Peroxyacetyl Nitrate (PAN) is the principal member of a family of nitrogenous compounds produced in polluted atmospheres by the action of sunlight on hydrocarbons and oxides of nitrogen. It is also important as a reservoir of oxides of nitrogen. It has been reported that a KI oxidant analyzer responds to PAN. However, quantitative studies of the sensitivity of the oxidant analyzer to PAN have not been well accomplished, especially for the standard method issued by Japan Environmental Agency, because of its thermochemical instability and difficulty of preparing standard sample gas of exact concentration.
In our study, we synthesized PAN authentically by the reaction of peroxyacetic acid with sodium nitrate using various alkanes as solvent and analyzed with ECD/gas chromatography. We found that n-pentane was the most suitable solvent in preparation and purification of PAN. Further, we prepared the standard samples of PAN at various concentrations and they were subjected to the measurement by the oxidant analyzer to examine the response of the analyzer to PAN. The concentration of PAN in the sample gas was determined by the infrared absorption spectrum of PAN using known absorptivity at its absorption bands. As a result we find that the sensitivity of the oxidant analyzer for PAN is 6.7 ± 0.5%.

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