中文关键词气溶胶光学特性黑碳覆盖物光吸收增强 英文关键词aerosoloptical propertieselement carboncoating materialslight absorption enhancement

作者	单位	E-mail
黄聪聪	南京信息工程大学环境科学与工程学院, 南京 210044 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044	hcc212@163.com
马嫣	南京信息工程大学环境科学与工程学院, 南京 210044 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044	my_nj@163.com
郑军	南京信息工程大学环境科学与工程学院, 南京 210044 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044

中文摘要 2016年1月1~19日在南京北郊利用三波长光声黑碳光度仪（PASS-3）对气溶胶的光学性质进行了实时在线观测，同时结合气溶胶化学组成分析了黑碳气溶胶的光吸收增强效应.结果表明，观测期间气溶胶在532 nm下的吸收系数、散射系数、单散射反照率的平均值为（64.19±35.28） Mm^-1、（454.68±238.71） Mm^-1、0.87±0.03，受边界层高度及颗粒物浓度的影响，呈现出明显的日变化特征.黑碳气溶胶的质量吸收截面（MAC）在观测期间的变化趋势为前期低，后期高，与非EC组分相对EC比值的变化趋势一致，受不同污染条件下二次物质的占比及覆盖物厚度变化的影响.基于MAC计算得到的405、532、781nm下的光吸收增强（EMAC）平均值分别为1.53±0.56、1.34±0.47、1.14±0.40，随着波长增加而降低，存在棕色碳（BrC）的贡献.各非EC组分相对EC的比值与EMAC均有一定相关性，其中OC/EC与EMAC相关性最高，说明有机物的积累是导致黑碳光吸收增强的主要原因.K⁺/EC与EMAC的高相关性表明生物质燃烧过程对光吸收增强也有一定影响. 英文摘要 A three-wavelength photoacoustic soot spectrometer (PASS-3) was employed for real-time online measurement of aerosol optical properties and light absorption enhancement of EC together with chemical composition analysis in the northern suburb of Nanjing during January 1-19, 2016. The average aerosol absorption coefficient, scattering coefficient, and single scattering albedo at 532 nm during the observation period were (64.19±35.28) Mm^-1, (454.68±238.71) Mm^-1, and 0.87±0.03, respectively, and showed clear diurnal variation, mainly affected by planetary boundary layer height and PM_2.5 mass concentration. The mass absorption cross section (MAC) showed an increasing trend during the observation period, consistent with the trend of variation in ratios between non-EC and EC components, resulting from the difference in relative percentage of secondary materials and coating thickness under different pollution conditions. The estimated light absorption enhancement, denoted E_MAC, was calculated based on the change in MAC. The campaign-averaged E_MAC at 405, 532, and 781 nm were 1.53±0.56, 1.34±0.47, and 1.14±0.40, respectively, showing a decrease with increasing wavelength, suggesting the contribution of brown carbon (BrC). All non-EC components showed linear correlation with E_MAC, with the most significant correlation between OC/EC and E_MAC, indicating that an increase in organics was likely the main contributor to light absorption enhancement in our study. In addition, the high correlation of K⁺/EC and E_MAC revealed the contribution of biomass burning.

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