Tsuyoshi Ohizumi
Analysis Group
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Featured researches published by Tsuyoshi Ohizumi.
Atmospheric Environment | 2002
Sinya Seto; Akira Nakamura; Izumi Noguchi; Tsuyoshi Ohizumi; Norio Fukuzaki; Syuji Toyama; Masahito Maeda; Kazuhiko Hayashi; Hiroshi Hara
Abstract Annual and seasonal trends were discussed for precipitation chemistry in Japan on the basis of a nationwide monitoring network by Japan Environment Agency. For this analysis, 17 sites, selected from the 23 network sites after evaluation of data completeness for the present purpose, were grouped into four areas in terms of the sea which could characterize each area: the Pacific Ocean, the Japan Sea, the Seto Inland Sea and the East China Sea areas. Major ion concentrations at each site were subjected to least-squares multiple regression analysis, and discussion was principally focused on the area-groups. Each area showed significant (p
Water Air and Soil Pollution | 1995
Hiroshi Hara; Moritsugu Kitamura; Atsuko Mori; Izumi Noguchi; Tsuyoshi Ohizumi; Sinya Seto; Tadashi Takeuchi; Teruyuki Deguchi
Precipitation chemistry in Japan was discussed on a wet-only sample database obtained in a nationwide survey from April 1989 to March 1993. Wet-only samples were collected at 29 stations over Japan on a biweekly basis. Commonly determined chemical parameters were measured in laboratories. The volume-weighted annual mean pH at each site ranged from 4.50 to 5.83 with a mean of 4.76. Concentration ranges and means (parenthesized) on an equivalent basis for major ions were as follows: nss-SO42−; 5.2–58.9 (38.6), NO3−; 1.8–25.0 (14.1), NH4+; 0.55–29.8 (18.3), nss-Ca2+; 2.0–34.5(14.2), Na+; 6.4–275.3 (49.1), Cl−; 13.7–322.4 (63.5) β eq L−1. Acid-base relationships for Phase-II records were quantitatively discussed in terms of three measures: pH, fractional acidity, and our proposed pAi.
Water Air and Soil Pollution | 2001
Norio Fukuzaki; Tsuyoshi Ohizumi; Kazuhide Matsuda
The geographical and temporal variations of chemical constituents in winter precipitation collected in the areas along the coast of the Sea of Japan (AASJ) were discussed by analyzing the data obtained in the 1st and 2nd National Add Deposition Survey by Japan Environmental Laboratories Associatioa In western Tohoku (WT) and Hokuriku (HR) areas in AASJ, in spite of large amounts of precipitation in winter; concentrations of non sea salt (nss-) are not as low as the other areas, and nss in these areas is lower than the other areas. As a result, FT concentrations of precipitation in these areas are somewhat higher than other areas. From the temporal analysis of daily sampled data and back trajectory analysis of air mass, it was found that the concentrations of nss-, and nss- are correlatively varied when air mass come from the Asian Continent, showing higher concentrations at the western sites in AASJ and depending on the meteorological conditions such as the direction of in flow air mass.
Water Air and Soil Pollution | 1995
Sinya Seto; Moritsugu Kitamura; Atsuko Mori; Izumi Noguchi; Tsuyoshi Ohizumi; Tadashi Takeuchi; Teruyuki Deguchi; H. Hara
A regression model of wet deposition on rainfall amount for non-seasalt sulfate (nss-SO42−) and nitrate (NO3−) was applied to a data set obtained through a nationwide survey from April 1989 to March 1993. Wet-only samples on a biweekly basis were collected at 29 sites over Japan. Reparameterized bivariate lognormal distribution was employed to describe the joint distribution of concentration (C) and rainfall amount (R) for each site. Ranges of geometric mean (μD) of biweekly deposition (D = C. R) for each site were 0.54–2.90 meq m−2 for nss-SU42−, and 0.21–1.36 meq m−22 for NO3−; that of biweekly rainfall amount (μR) was 24.1–78.0 mm. Urban or industrialized areas had high values of μD for these ions. Ranges of estimates of the slope of the regression equation of log(D/μD) on log(R/μR), were 0.45–0.99 for nss-SO42−, and 0.35–0.86 for NO3−; thus estimates of the slope for nss-SO42− tend to be larger than those for NO3−. The present analysis, consequently, statistically clarified some differences between the two ions in deposition processes which is understood in the light of current knowledge of atmospheric chemistry.
Science of The Total Environment | 2016
Yayoi Inomata; Tsuyoshi Ohizumi; Naoko Take; Keiichi Sato; Masataka Nishikawa
Sulfur isotopic ratios (δ(34)S) in size separated aerosol particles (PM2.5 and coarse particles) were measured at Niigata-Maki facing the Sea of Japan. Non-sea salt δ(34)S (δ(34)Snss) in PM2.5 showed seasonal variations with relatively high values in winter (1.0-3.9‰ in spring, 2.8-4.5‰ in summer, 1.3-4.5‰ in autumn, 3.7-5.7‰ in winter). Taking into consideration air mass transport routes, δ(34)Snss in the air masses which originated in the Asian continent and were transported over the Sea of Japan to the monitoring sites were higher than those values for air masses which were transported over the Japanese islands after leaving the Asian continent for each season. Considering that the δ(34)Snss in sulfuric acid derived from domestic emissions in Japan are lower than those of δ(34)Snss in coal, the lower δ(34)Snss for the air mass transported over the Japanese islands suggest that sulfuric acid in PM2.5 modified the δ(34)Snss due to aerosol mixing with sulfuric acid in Japan. Material balance calculations suggested that the relative contribution of transboundary transport in winter was also higher than for other seasons (40-75% in spring, 51-63% in summer, 45-73% in autumn, and 53-81% in winter). In particular, the contribution to the air masses which were transported directly from the Asian continent was relatively large (75% in spring, 59% in autumn, 78% in winter) in comparison with that for the air masses which were transported over Japan.
Nippon Kagaku Kaishi | 1997
Tsuyoshi Ohizumi; Toru Tabata; Moritsugu Kitamura; Sinya Seto; Tadashi Takeuchi; Teruyuki Deguchi; Izumi Noguchi; Atsuko Mori; Hiroshi Hara
Precipitation pH was automatically measured on site for each 0.5 mm-rainfall sample at 29 nationwide stations in Japan in Phase-II of Acid Deposition Survey from 1989 FY to 1992 FY by Japan Environment Agency. The mean pH of all of the stations over the entire survey period was pH 4.6. There was no pH record less than pH 3.0 which was supposed to affect plant growth. In western Japan and in remote islands in the Sea of Japan, lower pH was observed than in the other regions. Regarding seasonal variations, pH was rather lower in winter and spring. The mean pH of initial 0.5 mm-rainfall was lower than that of the whole rainfall at many stations, although it was higher at 8 stations. The monthly means of pH based on the automatic measurements of 0.5 mm-rainfall samples were compared with those from the manual measurements of biweekly samples, showing that the automatically determined pH was lower than the manually determined one by 0.3 pH unit on average. One of the possible causes of this pH difference is solution of alkali particles in the stored samples.
Atmospheric Environment | 1997
Tsuyoshi Ohizumi; Norio Fukuzaki; Minoru Kusakabe
Geochemical Journal | 2008
Minoru Kusakabe; Takeshi Ohba; Yutaka Yoshida; Hiroshi Satake; Tsuyoshi Ohizumi; William C. Evans; Gregory Tanyileke; George W. Kling
Atmospheric Environment | 2006
Kazuhide Matsuda; Ichiro Watanabe; Vitsanu Wingpud; Phunsak Theramongkol; Tsuyoshi Ohizumi
Atmospheric Environment | 2015
Hajime Akimoto; Yasuaki Mori; Kansuke Sasaki; Hiroto Nakanishi; Tsuyoshi Ohizumi; Yasuyuki Itano