基于场致电离荷电的大气细颗粒物粒径谱测量方法研究

Urban agglomeration regional atmospheric combine pollution has become more serious, and the concentration of atmospheric fine particles is rapidly increasing. So it is more meaningful of strengthening the fine particle size distribution measurement for analyzing the fine particle pollution characteristics and reason research. Light scatter method can't be used for nanoparticle detection, and the fine particle electronic mobility measurement can't provide a high sizing-resolution. The project will be started from fine particle charging character of field ionization process, with the target of searching the method for getting the fine particle size distribution under complex environment conditions. This project will be performed basing on fine particle charging model, and searching the function relationship of charge distribution, diameter and concentration. By constructing the platform of field ionization charged system and micro electric current detection system, the charging and losing efficiency will be measurement. And then, Multiple parameter model of fine particle charge distribution, number size distribution, and micro electric current will be instructed by Combining the fine particle charging model and experiment results. At last, fine particle size distribution extraction method will be bringing up. This project will establish theoretic and technical foundation for the particle number size distribution.

当前，城市群区域大气复合污染问题日益严重，大气细颗粒浓度不断升高，加强细颗粒物粒径谱分布测量对典型天气（如灰霾）条件下细颗粒物污染特征分析及追因溯源等具有重要意义。光散射方法无法实现纳米级细颗粒物的直接检测，而基于细颗粒物电迁移特性的测量方法难以实现粒径谱的高分辨快速测量。本课题从大气细颗粒物场致电离下的荷电特性入手，明确颗粒物电荷分布与自由离子密度、粒径谱分布之间的影响机理和变化关系，以实现大气细颗粒物粒径谱测量的原位快速测量。 本课题在建立颗粒物荷电模型的基础上，探寻细颗粒物电荷分布与粒径、浓度的函数关系；通过场致电离荷电系统及微电流检测系统平台搭建，完成颗粒物荷电效率和损失效率的测定；结合理论模拟与实验结果，构建电荷平衡状态下的颗粒物电荷分布、颗粒物粒径谱分布及微电流测量之间的多参数模型，最终获取颗粒物粒谱分布的提取方法，为颗粒物粒径及浓度的快速精确测量奠定理论和应用基础。

以臭氧和大气细颗粒浓度的不断升高为主要特征的大气复合型污染日益严重,各地灰霾事件频发，加强颗粒物粒径谱分布测量将更具现实意义。传统光散射方法无法实现纳米颗粒物测量，而基于颗粒物电迁率偏转测量的方法单次测量周期长、系统复杂、价格昂贵、难以维护，无法满足国内实际需求。为此我们研究了一种基于大气细颗粒物的荷电特性的粒径谱快速反演方法，在不依赖电迁移率测量的基础上，通过电荷分布模型构建、细颗粒物高效荷电系统搭建及参数测量、颗粒物微电流测量、粒径谱快速反演算法相结合，获得了基于微电流检测的大气细颗粒物粒径谱测量方法。.首先，完成了颗粒物荷电模型建立，获取细颗粒物电荷分布与粒径、浓度的函数关系，并数值模拟了细颗粒物在正电荷和负电荷荷电条件下的异同点。.其次，完成了基于场致电离的单极性、双极性荷电系统的平台搭建，实现了荷电系统工作电压、气流流速、荷电效率、损失效率等的测量；同时，完成了大气细颗粒物荷电微电流测试平台的搭建，实现了细颗粒物沉积微电流的初步测量。.最后，完成了基于细颗粒物微电流检测的粒径谱反演算法研究，给出了基于细颗粒物荷电的粒径谱迭代反演方法。