基于动力学演变过程的可吸入颗粒物光散射特性及其粒径分布的研究

The inhalable particles have caused many adverse effects on human health and environment, and the impact of inhalable particles in the atmosphere lies on the physicochemical properties of particles. Actually, all the physicochemical properties of inhalable particles not only depend on the particle size distribution, but also depend on the atmosphere environment. So the research on the particle size distribution of inhalable particles in the atmosphere has important significance. The light extinction method is usually applied to the particle sizing and concentration testing. In light extinction particle sizing technique, the particle size distribution can be obtained by the measurements of light extinction data at multiwavelengths and an appropriate inversion algorithm.In this method, the relationship between the particle size distribution and the extinction coefficient can be established by a mathematical model. The object of this project is about the inhalable particles in the atmosphere, and the main research work is to analyze the dynamic evolution processes of the inhalable particles in the atmosphere, and study the theoretical calculation method of light scattering for spherical and fiber non-spherical particles with different conditions, including the atmospheric motion, property of incident beam, particle size range, and then to obtain the evolutional tendency of extinction coefficient in the complex atmosphere environment. Meanwhile, the spherical and non-spherical dynamic particle size distribution inversion algorithms for the dilute and dense particle system are studied based on the dynamic light extinction data. The intention of this project is to provide sufficient theoretical basis for the on-line measurements of inhalable particle size distribution and concentration using the light extinction method, and then to improve the testing method for the inhalable particles and the forecast precision of the air quality.

可吸入颗粒物对环境、人类健康等都造成了许多不利的影响。可吸入颗粒物在大气中的作用取决于其物理化学性质。实际上，可吸入颗粒物的物理化学性质不但与粒径分布有关，而且受控于周围的大气环境。因此对处于大气环境中可吸入颗粒物的粒径分布进行研究具有重要意义。光谱消光法是颗粒粒径检测中一种常用的方法。该方法通过多波长光谱消光值以及适当的反演算法获得颗粒系的粒径分布。通过光谱消光法能够建立粒径分布与消光效率之间的数学模型。本项目以处于大气环境中的可吸入颗粒物为研究对象，分析大气环境中可吸入颗粒物粒径分布的动力学演变过程，研究在不同大气流动状态，不同入射光波束性质以及不同粒径范围条件下球形和纤维非球形颗粒光散射场的理论计算方法，进而获取复杂大气环境中球形和纤维非球形颗粒系动态消光效率的演变趋势。在此基础上，深入研究稀相和浓相颗粒系动态粒径分布的求解算法，从而提高可吸入颗粒物的检测手段以及空气质量的预报精度。

可吸入颗粒物对环境、人类健康等都造成了许多不利的影响。可吸入颗粒物在大气中的作用取决于其物理化学性质。实际上，可吸入颗粒物的物理化学性质不但与粒径分布有关，而且受控于周围的大气环境。因此对处于大气环境中可吸入颗粒物的粒径分布进行研究具有重要意义。本项目以光谱消光法为主要测量原理，利用多波长光谱消光值以及适当的反演算法获得大气环境中的可吸入颗粒物颗粒系的粒径分布。项目主要分析了大气环境中可吸入颗粒物粒径分布的动力学演变过程，研究在不同大气流动状态，不同入射光波束性质以及不同粒径范围条件下球形和非球形颗粒光散射场的理论计算方法，对颗粒系动力学演变过程进行深入研究，建立了动态光散射参量与颗粒动力学演变过程以及颗粒系统参数变化关系的数学模型，进而获取了复杂大气环境中球形和非球形颗粒系动态消光效率的演变趋势。在此基础上，深入研究了稀相和浓相颗粒系动态粒径分布的反演算法。本项目的研究，将为大气气溶胶生成、演变机理，流动特性等研究提供准确详实的实验数据和前期基础，从而提高可吸入颗粒物的检测手段以及空气质量的预报精度。