薛墨,傅月芸,蔡润龙,蒋靖坤,郝吉明.1~3 nm颗粒物在粒径分布测量仪中的通过效率研究[J].环境科学学报,2019,39(9):2896-2902
1~3 nm颗粒物在粒径分布测量仪中的通过效率研究
- Penetration of 1~3 nm particles through a diethylene glycol scanning mobility particle spectrometer (DEG-SMPS)
- 基金项目：国家自然科学基金面上项目（No.21896094）
- 薛墨
- 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084
- 傅月芸
- 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084
- 蔡润龙
- 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084
- 蒋靖坤
- 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084
- 郝吉明
- 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084
- 摘要：基于二甘醇的扫描电迁移率粒径谱仪（DEG-SMPS）是常用的1~3 nm颗粒物粒径分布测量系统.目前对1~3 nm颗粒物在该系统中通过效率的量化不够准确，这给大气颗粒物粒径分布的测量带来了较大的不确定性.本文研究了1~3 nm颗粒物和离子在直管、弯管以及气溶胶中和器等系统组件中的通过效率，并使用等效管长法来量化颗粒物在这些组件单元中的通过效率.研究表明，1~3 nm颗粒物在直管内的通过效率不受颗粒物电性影响，且可以由Gormley-Kennedy （G-K）方程估算.当采样流量为2.5 L·min-1时，DEG-SMPS系统中总等效管长约为433 cm，其中气溶胶中和器的等效管长为160 cm，弯头的等效管长为33 cm.
- Abstract：Diethylene glycol scanning mobility particle spectrometer (DEG-SMPS) system has been used for measuring the size distribution of 1~3 nm particles. However, penetration efficiency of 1~3 nm particles in DEG-SMPS is not accurately calculated, which increases the uncertainty of the measured 1~3 nm particle size distributions. In this study, the penetration efficiencies of 1~3 nm tungsten oxide particles and ions through different devices before entering the detector, including straight tubes, elbows, and an aerosol neutralizer are calibrated and the equivalent length method is used to describe particle penetration through these devices. The penetration efficiency through a straight tube can be estimated using the Gormley-Kennedy formula and it is negligibly affected by the charging polarity. At the sampling flow rate of 2.5 L·min-1, the equivalent length for the whole DEG-SMPS system is 433 cm, and for aerosol neutralizer and elbows are 160 cm and 33 cm, respectively.
