Develop a 3-D microscale roadway dispersion model and the application to assess urban population''s exposure

• Main Authors: Liu, Jyh-Jian, 劉志堅
• Other Authors: Jeng,Fu-Tien
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/43382474084574950485

博士 === 國立臺灣大學 === 環境工程研究所 === 82 === The complex building setting in urban shall induce complicated dispersion phenomena which is of microscale problem. On the basis of 2-D ROADWAY model, this study improve the numerical ROADWAY model to be of 3-D microscale model, and capable of treating the effect caused by building, and include the effect of vehicle- induced wake. The developed 3-D roadway model assume the validity of surface similarity theory, Eskridge vehicle-induced wake theory, vehicle speed much greater than wind speed, building setting continuously along roadway, no removal effect, and used only in the conditions of wind direction parallel to roadway, inert gas dispersion. The simulated concentrations comparing with measured data, input with actual traffic flow and wind data, at four stations by Taipei mainroad showed the difference averages of station were in the range of 1.5~3 ppm(as CO). The sensitivity analysis by the 3-D model found the factors were more sensitive to roadway concentration: emission rate (emission factor, traffic flow, vehicle speed), position of receptor, wind speed, building configuration. The study conducted commuting-pattern survey by questionnaire method in selected district, Taipei, and performed personal CO exposure measurements in the roadway- related micro- environments: automobile, motorcycle, bus, bus stop, walkway, residential and school areas, then estimate the 1-hour and 8-hour exposure in roadway by Monte-Carlo Simulation. The study found the commuting pattern in Taipei is different from that in U.S.. Regarding the 1-hour commuting exposure, commuters by bus and motorcycle modes were worse. The 8-hour exposure for driver (working in main roadway) and workers in offices were under- predicted and overpredicted, respectively, by the roadside fixed monitoring stations. The representativeness of fixed monitoring by roadside was limited to the people working at walksides only.