【摘要】 为了测量典型办公室内环境中环境烟草烟气悬浮颗粒物的数浓度和粒径分布变化,以及其对颗粒光散射的影响,在6.8 m×3.2m×2.8 m的试验间进行试验,采用测量范围为5~1 000 nm的DMS500扫描电迁移率粒径谱仪进行粒径测量。结果表明,不同卷烟样品的烟气粒径分布曲线近似,都可以用对数正态分布函数来描述。4种卷烟样品粒径分布及参数变化速率相似,在4 800 s内数中值粒径CMD平均值从105 nm增大至155 nm,几何标准差GSD平均值从1.58减小至1.45,CMD和GSD的变化趋势近似符合指数函数。利用基于Mueller光散射理论的程序计算烟颗粒对散射光的影响。粒径分布的变化显著改变了颗粒散射光强度,CMD最大使散射光强度增大7倍,GSD引起的强度变化较小。综合考虑烟气颗粒数浓度降低和粒径分布的变化,散射光强度最大增大3倍。更多还原

【Abstract】 The present study is inclined to identify the numerical concentration and the size distribution of the suspended fine particles( 11 000 nm) of the environmental tobacco smog( ETS) in a typical office indoor environment and the related impact of the various concentrations and sizes of ETS on the light-scattering intensity of the said fine particles. For the research goal,we have conducted all the experiments concerned in an office room with a square area of 6. 8 m × 3. 2 m × 2. 8 m. In the experiments we have tested the smoke produced by the four types of cigarettes,which we have detected by scanning the mobile particles in a size of DMS500 and the other particles with the sizes ranging from 5nm to 1 000 nm. The experimental results indicate that the particle size distribution curves of the smoke samples are in a great similarity. More detailedly speaking,the size distribution can be described by the log-normal distribution function of the two parameter variables. In the experiments we have noticed that the size distribution and the variation of the two parameters can be found very close to each other. In a period of 4 800 s in our experiment,the average particle of the calculated median diameter( CMD) proves to rise from 105 nm to 155 nm. In contrast,the mean geometric standard deviation( GSD) has been found decreasing from 1. 58 to 1. 45. What is more,the data fitting curve of CMD and GSD indicates the variation trend that approximately tends to comply with the exponential function. Besides,the numerical concentration of the environmental smoke also tends to decrease when the cigarettes were extinguished. The curve of the concentration has thus to be properly made fit for the polynomial functions. Furthermore,we have made a simulation of the impact of the variation of the suspended smoke particles on the intensity of light scattering by a computer program based on the Mueller Light Scattering Theory. The results of the numerical calculation on the light scattering of ETS particles imply that the intensity of the light scattering of the particles,whose intensity could approach to 800% to the maximum degree,should heavily rely on the value of the two parameters of the size distribution. In addition,the change of GSD is also likely to lead to a smaller variation of the scattering light intensity. Based on an overall analysis of the variation of size distribution and the decrease of smoke particle concentration as is shown above,it can be predicted that the multiple variation of the light scattering intensity of the environmental tobacco smog can be likely to go up as high as 3 times.更多还原