Pollutant Dispersion in an Urban Area
This chapter is composed by an introduction of existing prediction methodology of pollutant transportation and experimental observations of concentration fluctuation. In Sect. 5.2, the convective diffusion equation is derived from a balance of mass transportation, and approximated expression of average concentration theoretically derived from the transport equation is introduced. In Sect. 5.3, the results of wind tunnel experiment on downscaled model of existent urban area are indicated. The several characteristic points in urban area, such as highway, school ground, and in-between space of high-rise buildings, are selected as an occurrence point of pollutant. Instantaneous concentration is measured in-between of office buildings. The time of transport between source and measuring point is measured. The property of instantaneous concentration is discussed by focusing the probability density function (PDF) and the higher order moments, skewness, and kurtosis. These properties are linked to the distance between source and measuring point and condition of buildup area.
KeywordsUrban air pollution Unsteady emission Higher order moment Probability density function Gaussian plume model
The present research in Sect. 5.3 is financially supported by the sponsorship of MEXT (Ministry of Education, Culture, Sports, Science and Technology) of Japan from 2007 to 2009 and is conducted in corporation with Mitsubishi Heavy Industries.
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