On the Design of a Dust-fall Numerical Model
Date Issued
2006
Date
2006
Author(s)
Chang, Ying-Hsuan
DOI
zh-TW
Abstract
Suspend particulate and dustfall cause great air pollution problem in Taiwan. However, there is few research of air quality model about dustfall. The objective of this study is to build frame of air quality model about dustfall and to compare with the simulation concentration and dustfall amount in different setting of vertical resolution and particle size grading.
The results show the vertical resolution is sensitivity to concentration and dustfall amount of deposited particles. The height of first layer and the resolution under 100 m have great influence on simulation result. If the height of first layer is higher, the dustfall amount of particles larger than 50 μm is underestimate obviously and the concentration is overestimate. And if the number of grids in vertical direction is the same, the error is smaller when the resolution under 100 m is higher.
If particle size distribution is uniform, the results show that the error between different division of particle size becomes larger as downwind distance gets longer. In this size grade of particles less than 10 μm, the maximum error is less than 5 % by using only one size particle to simulate. In the size grade of particles between 10 to 50 μm and 50 to 100 μm, the maximum error are both within 10% when the size are divided into two grade. It shows a division of particle size into five grade is enough to simulate suspend particulate and dustfall.
Subjects
落塵模式
垂直解析度
粒徑分級
Dustfall model
Vertical resolution
Particle size grading
Type
thesis