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Hiroshi Hayami,Yuta Iga,Syuichi Itahashi,Kazuhiko Miura,Tatsuhiro Mori,Tatsuya Sakurai 한국대기환경학회 2022 Asian Journal of Atmospheric Environment (AJAE) Vol.16 No.3
The global limit on the sulfur content of ship fuel was reduced from 3.50% to 0.50% in January 2020 to reduce ship emissions of SO2 and particulate matter. We conducted observational campaigns before and after the new global limit was introduced to detect changes in coastal air quality. We measured ambient concentrations of SO2 and CO2 ship plumes on shore with the sniffing method under the Kanmon Bridge over the Kanmon Straits between Honshu and Kyusyu Islands, Japan, for several weeks in August to September in 2019 and 2020. The fuel sulfur content (FSC) estimated from our measurements mainly varied from 0.50% to 3.00% in 2019, whereas the range narrowed to 0.10% to 0.40% in 2020, showing that all the ships complied. The mean FSC in 2020 was reduced to 16% of that in 2019, which was consistent with the reduction in the ambient SO2 concentration. Sakurai et al. (2021) estimated that after the 2020 global limit was brought in, SO2 emissions from ships were reduced to 24% of their previous values by assuming that all ships have a FSC of 0.50%. Our results indicate the 2020 global limit led to much greater reductions in SO2 emissions from ships than expected.
Spatiotemporal Variations of Fine Particulate Organic and Elemental Carbons in Greater Tokyo
Hiroshi Hayami,Shinji Saito,Shuichi Hasegawa 한국대기환경학회 2019 Asian Journal of Atmospheric Environment (AJAE) Vol.13 No.3
Hourly concentrations of fine particulate OC and EC are monitored for more than one year by optical monitors at three sites in and out of Tokyo, Japan. Distances between the sites are 20 to 50 km. SOC concentrations are estimated from the OC and EC concentrations by an EC tracer method. Site A in an industrial site shows higher EC concentrations than site B in a residential area, but differences between the sites are much reduced for OC. Site C in a rural area, where measurements are available in colder months, shows pronounced seasonal variations with high peaks in October and December and characteristic diurnal variations in OC with the highest in the evening in October, due probably to open field burning. Photochemical formation of SOC is suggested but does not rise up so much OC concentrations in summer, which are quite lower than other seasons. A comparison between relative concentrations of EC among the sites and local emissions amounts indicates missing or considerable underestimation of EC emissions near the rural site C. Time lag correlations suggest transport of OC produced by open field burning around site C to site A. These findings would be useful for improving model performances in OC/EC predictions.
Dynamic PIV Measurement of Swirl Flow in a PC Fan
Shinichiro ARAMAKI,Hiroshi HAYAMI 한국가시화정보학회 2004 KOREA-JAPAN Joint Seminar on Particle Image Veloci Vol.- No.-
The dynamic particle image velocimetry (PIV) is consisted of a high frequency pulse laser, high speed cameras and a timing controller. The three velocity components of flow downstream of an axial flow fan for PC cooling system are measured using the dynamic PIV system. An Axial flow fan has seven blades of 72 ㎜ in diameter. The rotating speed is 1800 rpm. The downstream flow is visualized by smoke particles of about 0.3-1 ㎛ in diameter. The three-dimensional instantaneous velocity fields are measured at three downstream planes. The swirl velocity component was diffused downstream and the change in time-mean vorticity distribution downstream was also discussed. The spatio-temporal change in axial velocity component with the blades passing is recognized by the instantaneous vector maps. And the dynamic behavior of vorticity moving with the rotating blades is discussed using the unsteady vorticity maps.
Numerical Simulation of Extreme Air Pollution by Fine Particulate Matter in China in Winter 2013
Hikari Shimadera,Hiroshi Hayami,Toshimasa Ohara,Yu Morino,Akinori Takami,Satoshi Irei 한국대기환경학회 2014 Asian Journal of Atmospheric Environment (AJAE) Vol.8 No.1
In winter 2013, extreme air pollution by fine particulatematter (PM2.5) in China attracted much publicattention. In order to simulate the PM2.5 pollution,the Community Multiscale Air Quality model drivenby the Weather Research and Forecasting model wasapplied to East Asia in a period from 1 January 2013to 5 February 2013. The model generally reproducedPM2.5 concentration in China with emission data inthe year 2006. Therefore, the extreme PM2.5 pollutionseems to be mainly attributed to meteorological (weakwind and stable) conditions rather than emissionincreases in the past several years. The model wellsimulated temporal and spatial variations in PM2.5concentrations in Japan as well as China, indicatingthat the model well captured characteristics of thePM2.5 pollutions in both areas on the windward andleeward sides in East Asia in the study period. Inaddition, contribution rates of four anthropogenicemission sectors (power generation, industrial, residentialand transportation) in China to PM2.5 concentrationwere estimated by conducting zero-out emissionsensitivity runs. Among the four sectors, the residentialsector had the highest contribution to PM2.5concentration. Therefore, the extreme PM2.5 pollutionmay be also attributed to large emissions from combustionfor heating in cold regions in China.