为探究雾霾粒子吸湿性引起的散射吸湿增长特性,基于雾霾粒子湿度增长模型,利用Mie散射理论和多球T矩阵计算方法,详细研究了硫酸、硫酸铵、沙尘、硝酸铵以及碳质气溶胶5种典型雾霾粒子及其团簇在入射波长为532 nm、相对湿度在60%~95%范围内的散射吸湿增长特性。研究结果表明:对单一雾霾粒子,硫酸、硫酸铵以及硝酸铵这类二次水溶性无机粒子及其团簇的散射吸湿增长较突出,沙尘较为平缓,而碳质气溶胶则呈现抑制作用,同时,小粒径粒子的散射吸湿增长因子呈指数增长,而大粒径粒子则呈波动、负增长趋势;对于雾霾粒子的团簇,散射吸湿增长因子曲线整体增幅减小,粒子团簇的体积分数对散射吸湿的影响明显,随着体积分数的增加,散射吸湿增长因子曲线的波动频率增大,同时振幅减小,但整体呈现的吸湿增长还是由团簇粒子的粒径范围与成分决定,其中团簇粒径范围影响较大。这为探究雾霾粒子散射吸湿增长特性和研究大气污染提供了理论支持。

In order to explore the scattering hygroscopic growth characteristics of haze particles caused by hygroscopicity, based on the humidity growth model of haze particles, we used the Mie scattering theory and multi-sphere T-matrix calculation method to study the scattering hygroscopic growth characteristics of five typical kinds of haze particles and their clusters when the incident wavelength was 532 nm and the relative humidity range was 60%-95%. The results demonstrate that for a single kind of haze particle, secondary water-soluble inorganic particles and clusters, such as sulfuric acid, ammonium sulfate, and ammonium nitrate, show prominent scattering hygroscopic growth. In comparison, the scattering hygroscopic growth is gentle for dust and inhibitory for carbonaceous aerosols. Meanwhile, the scattering hygroscopic growth of small particles is exponential, while that of large particles fluctuates with a negative growth trend. For the clusters of haze particles, the curve of scattering hygroscopic growth factor exhibits a declined overall increment. The volume fraction of the particle clusters has an obvious effect on the scattering hygroscopicity. Moreover, with an increase of the volume fraction, the curve of scattering hygroscopic growth factor has a higher fluctuation frequency and a smaller amplitude. However, the overall hygroscopic growth is determined by the size range and composition of cluster particles, and the size range of clusters has a greater impact. In conclusion, this study provides theoretical support for the research on the scattering hygroscopic growth characteristics and air pollution of haze particles.