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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.
Determination of BVOCs based on high time-resolved measurements in urban and forest areas in Japan
Yujiro Ichikawa,Kiyoshi Nojiri,Kouki Sasaka 한국대기환경학회 2023 Asian Journal of Atmospheric Environment (AJAE) Vol.17 No.1
Biogenic volatile organic compounds (BVOCs) with high photochemical activity and short atmospheric lifetimes are major contributors to tropospheric ozone and other photochemical air pollution. Although several studies have been conducted on BVOC emissions in Japan, no comprehensive observations have been made to determine the actual state of BVOCs in the atmosphere. Therefore, we conducted time-resolved measurements of atmospheric BVOCs in urban and forested areas throughout the year. The concentrations of BVOCs were higher in summer than in the other seasons. Isoprene concentrations were higher during hours with higher temperatures and solar radiation. However, there were also months and times of the year when monoterpenes showed high concentrations, which indicates that the behavior of the BVOC components differed depending on the time of the year. The results of the propylene equivalent concentration indicated that BVOCs considerably contributed to tropospheric ozone production. The year-long observations of BVOCs in this study contribute to our understanding of the actual status of atmospheric BVOC concentrations and components and the uncertainty in the calculation results of chemical transport models.