静风条件下烟尘扩散地面浓度模式的研究

Research On Ground Concentration Mode of Dust Particle Diffusion Under Calm Condition

利用大气扩散理论分析了静风和重力沉降两种作用对尘粒在大气中扩散的影响;指出高架连续点源的尘粒扩散在静风条件下呈现蘑菇状烟云,地面浓度值只与其距污染源的直线距离有关;建立了相应的正态分布地面浓度扩散模式,并且确定该模式扩散参数的表达式.应用该模式可简便地预测最大地面浓度c_m,最大地面浓度出现距离x_m及扩散范围;由于模式中地面浓度计算值的量纲为单位面积、单位时间的质量沉积率,因而统一了地面浓度计算值与常规监测值的量纲,使计算结果与常规监测值之间具有可比性.

The atmosphere dispersion theory was used to analyze the influence ol calm wind and gravity action on the diffusion of dust particles . The model of normal distribution and diffusion of particles on ground was established and the expression of diffusion parameters of the model was determined. The result shows that the ground concentration is related only to the distance between the monitoring point and the pollution source. By using this model, it can be very convenient to evaluate the peak value of ground concentration cm, the distance xmbetween this peak point and the pollution source, and the diffusion range. Since the ground concentration value dimension is the quality deposition rate of unit area and unit time, The model also unifies the dimensions of both ground concentration value and the conventional monitoring one, making it very easy to compare the conventional monitoring value with the calculated result.