【摘要】 作者对本地区某大型电厂燃煤及烟道灰中天然铀、钍含量进行了测定,对1980年全年的逐时气象资料进行了分析,采用P-T法进行天气稳定度分类,计算了风向、稳定度、风速联合频率f_ijk及降雨的风向频率f_rljk,估算了该厂气载排出物（烟尘）造成厂区外周围半径60km范围内近地面空气中天然铀、钍的污染浓度,地面沉积量及其分布。计算中对高空风速、烟云抬升、静风及沉积（特别是降雨引起的湿沉积）引起的空气污染浓度降低进行了必要的修正。 计算结果表明,空气最大年平均污染浓度出现在SE方位1km处,该处U_max=1.95×10^-7mg·m^-3,X_Thmax=3.45×10^-7mg·m^-3。在距烟囱10km以内的范围内,地面沉积量主要来自降雨冲洗造成的湿沉积,10km以外则应同时考虑于沉积的贡献。更多还原

【Abstract】 The authors determined the contents of natural uranium and thorium in coal and tunnel ash samples taken from a large coal-fired power station in the nearby area.The hourly climate data in 1980 are analysed and the atmospheric stability is cataloged by pasquill-Turner method. Wind direction-atmospheric stability-wind velocity combined probabilities fijk and rain-wind direction probabilities f,ijk are calculated. The near ground air pollution concentrations, the ground depositions and the distributions of U,., and Thn.t presented in airborne effluent (fly ash) within an area round the station with a radius of 60 km are also estimated. In the calculations, some factors such as wind velocity in the higher atmosphere, plume rise still wind and decrease of air pollution concentration by the ground deposition (especially the wet deposition porduced by rain) have been considered. Some corrections necessary for the factors described above are also made.It is shown that the maximum annual average airPollution concentration^,^,* = 1.95 x 10-7mg-m-3, YThm,I = 3.45 x 10~7mg ?m~s) appears at the point 1 km away from the source in the fan SE.In the area round the station with a radius shorter than 10 km, the ground deposition is mainly by the wet deposition, but, where the radius longer than 10 km, the dry deposition must be taken into account.更多还原