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Kazuhiko Sakamoto,Tomohiro Sakaguchi,Zhaowu Jiang,Tarek Mohamed Naser,Kazuhiko Sekiguchi,Qingyue Wang,Katsuyuki Takahashi 한국대기환경학회 2007 한국대기환경학회 학술대회논문집 Vol.- No.-
To clarify the effect of the Diesel Vehicle Exhaust Gas Regulations enforced by Tokyo Metropolis, Saitama, Kanagawa, and Chiba Prefectures in October, 2003, we compared concentration of various chemical components in size-separated SPM and traffic volume of 2002 or 2003 (before the Regulation) to that of 2003 or 2004 (after the Regulation) at the road site of National Road Route 17 and Prefecture Road Route 57. Generally, decreasing tendency in EC concentration of each particle sizes was found from 2002 and 2003 to 2003 and 2004 sampling periods, respectively. Especially, decrease in average concentration of EC<SUB><2㎛</SUB> was clear. In the next, we analyzed various correlations of chemical components in size-separated SPM and traffic volume. From their results, we concluded decrease of the EC<SUB><2㎛</SUB> concentration at the roadside was caused by this Regulation. Also, we will discuss on long term trend of mass concentrations and chemical composition for SPM and fine particles observed at general environment and around the other trunk roads in the greater Tokyo Metropolitan Area.
Bao, Linfa,Sakamoto, Kazuhiko Korean Society for Atmospheric Environment 2009 Asian Journal of Atmospheric Environment (AJAE) Vol.3 No.1
Saturated n-dicarboxylic acids ($C_2-C_7$, $C_9$), unsaturated dicarboxylic acids (maleic, fumaric, phthalic acid), ketocarboxylic acids (pyruvic, glyoxylic acid), and dicarbonyls (glyoxal, methylglyoxal) were determined in size-segregated samples with a high-volume Andersen air sampler at a suburban site in Saitama, Japan, May 12-17 and July 24-27, 2007 and January 22-31, 2008. The seasonal average concentrations of these detected organic acids were 670 $ng/m^3$, accounting for about 4.4-5.7% (C/C) of water-soluble organic carbon (WSOC) and 2.3-3.6% (C/C) of organic carbon (OC). The most abundant species of dicarboxylic acids was oxalic acid, followed by malonic, phthalic, or succinic acids. Glyoxylic acid and methyglyoxal were most abundant ketocarboxylic acid and dicarbonyl, respectively. Seasonal differences, size-segregated concentrations, and the correlations of these acids with ambient temperatures, oxidants, elemental carbon (EC), OC, WSOC, and ionic components were also discussed in terms of their corresponding sources and possible secondary formation pathways. The results suggested that photochemical reactions contributed more to the formation of particulate organic acids in Saitama suburban areas than did direct emissions from anthropogenic and natural sources. However, direct emissions of vehicles were also important sources of several organic acids in particles, such as phthalic and adipic acids, especially in winter.
Kouki Sasaka,Qingyue Wang,Kazuhiko Sakamoto 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.3
In Japan, the primary carbonaceous particles emitted from motor vehicles and waste incinerators have been reduced due to strict regulations against exhaust gas. However, the relative contribution of carbonaceous particles derived from plants and biomass has been increasing. Accordingly, compositional analysis of carbonaceous particles has become increasingly important to determine the sources and types of particles produced. To reveal the sources of the organic particles contained in particulate matter with diameters of ≤ 2.5 μm (PM2.5) and the processes involved in their generation, we analyzed molecular marker compounds (2-methyltetrols, cis-pinonic acid, and levoglucosan) derived from the plants and biomass in the PM2.5 collected during daytime- and nighttime-sampling periods in summer (July and August) and autumn (November) in Kazo, which is in the northern area of Saitama prefecture, Japan. We also measured 14C carbonaceous concentrations in the same PM2.5 samples. The concentrations of 2-methyltetrols were higher in the summer than in the autumn. Because the deciduous period overlaps with this decrease in the levels of 2-methyltetrols, we considered the emission source to broad-leaved trees. In contrast, the emission source of the cispinonic acid precursor was considered to be conifers, because its concentration remained almost constant throughout the year. The concentration of levoglucosan was considerably increased in the autumn due to frequent biomass open burning. The ratio of plantderived carbon to total carbon, obtained by measuring of 14C, in summer PM2.5 sample was higher in the nighttime, and could be influenced by anthropogenic sources during the daytime.
Ricardo Ortiz,Satoru Shimada,Kazuhiko Sekiguchi,Qinyue Wang,Kazuhiko Sakamoto 한국대기환경학회 2013 Asian Journal of Atmospheric Environment (AJAE) Vol.7 No.3
Seven potentially harmful bifunctional carbonyls were measured in particulate and gaseous phases at a roadside site and a suburban site in an area about 30 km north-northwest from Tokyo metropolitan area in the Kanto region in Japan. For the first time, these compounds were measured in both phases with a time resolution of 2 h. We found that wind direction is an important parameter that affects the collection of these compounds near the source, and it can cover the effects of other important variables. Our results confirmed that motor vehicles and especially diesel fuelled vehicles are important sources of these compounds. Photochemical generation is also an important source of these compounds in the gaseous phase. Transportation from the urban area is also important,particularly in the aerosol phase.
Hauazawa, Atsushi,Gao, Shidong,Sakamoto, Kazuhiko Korean Society for Atmospheric Environment 2008 Asian Journal of Atmospheric Environment (AJAE) Vol.2 No.2
In China, energy and environmental problems are becoming serious owing to rapid economic development. Coal is the most problematic energy source because it causes indoor and outdoor air pollution, acid rain, and global warming. One type of clean coal technology that has been developed is the coal-biomass briquette (or bio-briquette, BB) technique. BBs, which are produced from pulverized coal, biomass (typically, agricultural waste), and a sulfur fixation agent (slaked lime, $Ca(OH)_2$) under high pressure without any binder, have a high sulfur-fixation effect. In addition, BB combustion ash, that is, the waste material, can be used as a neutralization agent for acidic soil because of its high alkalinity, which originates from the added slaked lime. In this study, we evaluated the suitability of alternative biomass sources, namely, aquatic plants, as a BB constituent from the perspective of their use as a source of energy. We selected three types of aquatic plants for use in BB preparation and compared the fuel, handling, and environmental characteristics of the new BBs with those of conventional BBs. Our results showed that air-dried aquatic plants had a higher calorific value, which was in proportion to their carbon content, than agricultural waste biomass; the compressive strength of the new BBs, which depends on the lignin content of the biomass, was high enough to bear long-range intracontinental transport in China; and the new BBs had the same emission control capacity as the conventional BBs.
Naser, TarekMohamed,Yoshimura, Yuji,Sekiguchi, Kazuhiko,Wang, Qingyue,Sakamoto, Kazuhiko Korean Society for Atmospheric Environment 2008 Asian Journal of Atmospheric Environment (AJAE) Vol.2 No.2
The chemical compositions of $PM_{2.5}$ and $PM_{10}$ and associated high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) were investigated during winter and summer at a roadside and an urban background site in Saitama, Japan. The average concentrations of $PM_{2.5}$ exceeded the United States Environmental Protection Agency standards during both periods. Carbonaceous components were abundant in both the observed and calculated (by means of a mass closure model) chemical composition of $PM_{2.5}$. Traffic-related pollutants (elemental carbon and high-molecular-weight PAHs) were strongly associated with $PM_{2.5}$ rather than with larger particles. The mass concentrations of $PM_{2.5}$, as well as those of EC and PAHs associated with the particles, at the two sites were strongly correlated. Comparison of our data with source profile ratios indicates that diesel-powered vehicles were probably the main source of the measured PAHs. The PAHs concentrations were affected by meteorological conditions during our study. Our results highlight the need for the establishment of standards for $PM_{2.5}$ in Japan.
Long-term Sulfur Emissions and Environmental Kuznets Curves: Comparison and Implications
Huang, Zheng,Tonooka, Yutaka,Sekiguchi, Kazuhiko,Wang, Qingyue,Sakamoto, Kazuhiko Korean Society for Atmospheric Environment 2009 Asian Journal of Atmospheric Environment (AJAE) Vol.3 No.1
The environmental Kuznets curve hypothesis assumes an inverted U-shaped relationship between environmental damage and income, and such curves have been used to study how economic growth affects the environment. In this study, we analyzed data for gross domestic product (GDP) per capita and for sulfur emissions in the industrialized countries of the United Kingdom, United States of America, and Japan, as well as data for the developing country of China, to determine the relationship between emissions and income in these countries. Attempts by these countries' governments to incorporate environmental policy considerations into the income-environment relationship were also examined. The potential role of the environmental Kuznets curve as a policy tool was investigated. We determined that, at least in the case of sulfur emissions, policies and institutions significantly reduced environmental degradation in the industrialized countries studied. Furthermore, the environmental Kuznets curve can reliably predict the future relationship between environmental impact and GDP for developing countries.