|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1995 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1994 : ¥1,100,000 (Direct Cost : ¥1,100,000)
It is widely known that during late autumn to early winter concerntration of nitrogen dioxide becomes very high over Kanto, Nohbi Plains etc., and thus atmospheric environment tends to be worse. This may be partly due to the characteristic meteorological condition in this season, when just before the beginning of winter monsoon synoptic scale wind is generally weak under periodically-passing high pressure systems, and in addition lacal wind such as sea breeze never develops strong because of adverse thermal condition during daytime, i. e. temperatures over land surface exceed those over sea by only 1 to 2 deg for only 2 hours a day. In this study to elucidate characteristics of air pollution transport we have performed 3D simulation for the transport/chemistry/deposition of air pollutants over Nohbi plain and Ise bay area. The simulated days were 24 and 25 November, 1992, when extensive field observations using air plane, rawin-sondes, Doppler-sodar, and many ground-based monitoring st
ations were conducted.
Obtained results are as follows :
(1)Emission source inventories were investigated for Nohbi plain. Non-methane VOCs (Volatile Organic hydroCarbons) emission distributions were estimated on the basis of emission strength per unit production, fuel consumption, etc. and spatial distributions of industrial production, number of cars etc. Furthermore, these emission sources were tested and corrected by using 1D diffusion/chemistry model so that calculated vertical profiles of VOCs concentrations agree with those observed. Using this procedure, emissions of aromatic hydrocarbons such as toluene and xylene were reevaluated and cut to one-ninth of the initial estimation.
(2)With these emission enventories, two days 3D transport/chemistry/deposition simulation was performed for most of important chemical species which include NO,NO_2, HNO_3, SO_2, SO_4^=, O_3, H_2O_2, VOCs etc. The simulation resultsshowed : (i) good agreement between calculated and observed NO_2 concentrations at surface level, (ii) important features of observed concentration distributions at 300 and 600 m high were well reproduced by the simulation, i. e. high concentration zones appear over Chita peninsula and Mikawa bay area during daytime, indicating strong mixing activity over Nohbi plain which is in upstream area of Chita and Mikawa.
(3)Detailed analysis of the obtained results is left for investigation of effecte emission control in this region. Less