城市大气亚微粒子理化特征的变化对气溶胶散射效率的影响

大气亚微粒子PM1对空气质量、能见度和气候变化至关重要，其含量变化对气溶胶的散射影响很大。以往常用细粒子PM2.5的散射特征来研究灰霾粒子的辐射强迫，很少考虑PM2.5中PM1含量变化，难以准确解释雾霾天气气溶胶辐射变化的规律。本研究选择河南—开封，借助多种气溶胶观测仪器，同步开展PM1和PM2.5化学成分、散射特性、吸湿增长及气体污染物综合观测。首先结合气象参数，研究雾霾天气PM1和PM2.5二次组分形成机理和吸湿增长变化特征；其次揭示PM1和PM2.5二次组分差异的驱动机制，探讨二次组分和吸湿增长之间的关系，最后阐明PM2.5中PM1含量、二次化学组分、吸湿增长变化对PM2.5散射效率影响，通过回归分析，给出包含PM1含量变化的初步参数化的气溶胶散射效率的评估模型，以便弥补亚微粒子含量变化影响气溶胶散射强度不确定性，并为今后气候模式中粒子大小对气溶胶辐射强迫影响参数化提供数据支持。

Submicron particles (PM1) have a serious impact on air quality, visibility and climate, and the variation of PM1 content in aerosol has a great influence on aerosol scattering. In the past, the characteristics of PM2.5 light scattering were commonly used to study the radiative forcing of aerosols, and the variation of PM1 content in PM2.5 was rarely considered, so it is difficult to accurately explain the variation of aerosol radiation in haze weather. In this study, the chemical composition, light scattering , and hygroscopic growth of PM1 and PM2.5 and gas pollutants were simultaneously observed in Kaifeng of henan province with the help of a variety of aerosol observation instruments. Firstly, combined with meteorological parameters, the secondary formation mechanism and hygroscopic growth of PM1 and PM2.5 in haze weather are studied. Secondly, the driving mechanism of the secondary component difference of PM1 and PM2.5 is revealed, and the relationship between the secondary component and hygroscopicity is discussed. Finally, the influence of dynamic variation of PM1 content, secondary chemical component and hygroscopic growth on PM2.5 scattering efficiency is clarified, and a model for assessing aerosol scattering efficiency including the preliminary parameters of PM1 content dynamics is presented is given through regression statistics. This results will make up for the uncertainty of aerosol scattering intensity caused by the change of sub particle content and provide data support for the parameterization of the effect of particle size on aerosol radiative forcing in future climate models.