| Project/Area Number |
01550431
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
都市工学・衛生工学
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| Research Institution | National Institution for Environmental Studies |
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Principal Investigator |
WAKAMATSU Shinji National Institute for Environmental Studies ; Regional Environment Division, Head of Urban Air Quality Research Team., 地域環境研究グループ・都市大気保全研究チーム, 総合研究官 (70109502)
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| Co-Investigator(Kenkyū-buntansha) |
WAKAMATSU Shinji (70109502)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Urban air pollution / Photochemical air pollution / Nitorgen oxides / Air pollution model / 都市大気保全 / 高濃度大気汚染 / 複合大気汚染 / 大気汚染予測モデル / 感度解析 / 大気汚染制御 / 窒素酸化物汚染 |
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| Research Abstract |
To clarify the urban air pollution formation mechanism aid its control atrategy air pollution simulation models were applied based on the field observation data.
For the summer season photochemical ozone study a three-dimensional urban airshed model was applied. Model predictions have been compared with observed concentration value for the Tokyo area. The results indicate that the patterns of simulated and observed O_3 concentrations are in qualitative agreement. However, a sensitivity analysis has indicated that choice of boundry conditions for initial concentrations has an important influence on model porediction if the monitoring station is close to the region boundaries. It is significant to note that determining "how close" a station is to the boundaries is a function of the wind direction. Model predictions are also quite sensitive to the mass ratio of NMHC/NOx emission. Consequently, mis-specification of the emission inventory can lead to major to differences between observed and calculated O_3 concetrations.
For the winter season nitrogen oxides study NO_2 concentration was analyzed and a photochemical box model (PBM) was applied to clarify the temporal variation of pollutants. Calculated results showed that during the morning hours, reaction with NO and background O_3 plays an important role for the concentration of NO_2, while in the afternoon the contribution of photochemical reactions becomes important, Also, it was concluded that the effect of photochemical reactions (oxidation of NO to NO_2) and the transformation from NOx to PAN and HNO_3 play the significant role even in the winterseason. These effects decrease the midafternoon concentration of NO_2, however, these photochemically generated secondary pollutants during the day accelerate the increase of NO_2 concentration in the evening.
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