二氧化氮的非均相反应对矿质颗粒物冰核活性的影响
Effects of heterogeneous reaction with NO2 on ice nucleation activities of feldspar and Arizona Test Dust
Lanxiadi Chen, Chao Peng, Jingchuan Chen, Jie Chen, Wenjun Gu, Xiaohong Jia, Zhijun Wu, Qiyuan Wang, Mingjin Tang*
https://doi.org/10.1016/j.jes.2022.04.034
摘要
冰核颗粒物是指在大气中可以引起水蒸汽发生凝华或过冷液滴发生冻结而形成冰晶的气溶胶颗粒物。通常情况下，纯水通过均质核化过程形成冰晶只能在-38oC以下发生，而冰核颗粒物的存在可以使冰晶在相对更高的温度下形成。因此，冰核颗粒物将影响云的形成、性质和寿命，继而影响地球系统的辐射和能量平衡以及降水的形成。矿质颗粒物是对流层中最重要的冰核颗粒物之一。然而，二氧化氮的非均相反应对矿质颗粒物冰核活性的影响仍有待阐明。
本研究开发了一种测定大气颗粒物冰核活性的方法，并将该方法用于探究二氧化氮的非均相反应对矿质颗粒物冰核活性的影响。我们发现，二氧化氮的非均相反应可显著降低长石和亚利桑那沙尘的冰核活性。具体来说，在反应0至6小时期间，长石颗粒物表面由于非均相反应生成的硝酸盐含量随反应时间的增加而逐渐升高；同时，长石的冰核活性却随着反应时间的增加而逐渐降低。然而，当反应时间进一步延长至24小时后，长石的硝酸盐含量和冰核活性并没有发生显著改变。对于亚利桑那沙尘，我们发现在反应0至24小时期间，亚利桑那沙尘的硝酸盐含量随反应时间的增加而逐渐升高；同时，其冰核活性逐渐降低。该研究有助于我们更好地了解二氧化氮的非均相反应对矿质颗粒物冰核活性的影响，也将从基础水平上揭示颗粒物冰核活性位点的性质。
亮点
本研究首次发现二氧化氮的非均相反应可降低矿质颗粒物的冰核活性。
二氧化氮的非均相反应对矿质颗粒物冰核活性的影响
Abstract
Mineral dust is an important type of ice nucleating particles in the troposphere; however, the effects of heterogeneous reactions on ice nucleation (IN) activities of mineral dust remain to be elucidated. A droplet-freezing apparatus (Guangzhou Institute of Geochemistry Ice Nucleation Apparatus, GIGINA) was developed in this work to measure IN activities of atmospheric particles in the immersion freezing mode, and its performance was validated by a series of experimental characterizations. This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust (ATD) particles before and after heterogeneous reaction with NO2 (10 ± 0.5 ppmv) at 40% relative humidity. The surface coverage of nitrate, θ(NO3-), increased to 3.1 ± 0.2 for feldspar after reaction with NO2 for 6 hr, and meanwhile the active site density per unit surface area (ns) at -20oC was reduced from 92 ± 5 to < 1.0 cm-2 by about two orders of magnitude; however, no changes in nitrate content or IN activities were observed for further increase in reaction time (up to 24 hr). Both nitrate content and IN activities changed continuously with reaction time (up to 24 hr) for ATD particles; after reaction with NO2 for 24 hr, θ(NO3-) increased to 1.4 ± 0.1 and ns at -20oC was reduced from 20 ± 4 to 9.7 ± 1.9 cm-2 by a factor of ~ 2. Our work suggests that heterogeneous reaction with NO2, an abundant reactive nitrogen species in the troposphere, may significantly reduce IN activities of mineral dust in the immersion freezing mode.
作者简介
第一作者
陈兰夏迪，中国科学院广州地球化学研究所在读博士生。在此期间前往加拿大英属哥伦比亚大学交换学习了近一年。主要研究方向为矿质颗粒物的吸湿性和冰核活性及老化过程的影响。目前已作为第一作者在Atmos. Chem. Phys.、J. Geophys. Res.-Atmos等国际SCI期刊上发表论文4篇，在《中国环境科学》上发表中文EI论文一篇。荣曾获“硕士研究生国家奖学金”、“中科集团环保奖学金”等奖项。
通讯作者
唐明金，中国科学院广州地球化学研究所研究员、博士生导师。主要研究方向为气溶胶化学与地球化学，重点关注沙尘气溶胶的大气化学及其环境效应。在Chem. Rev.、Atmos. Chem. Phys.等期刊上发表论文80多篇。自2017年起担任Atmospheric Measurement Techniques副主编，2023年当选国际全球大气化学研究计划（IGAC）科学指导委员会委员。
原文链接
https://www.sciencedirect.com/science/article/pii/S1001074222002145
引用格式
Lanxiadi Chen, Chao Peng, Jingchuan Chen, Jie Chen, Wenjun Gu, Xiaohong Jia, Zhijun Wu, Qiyuan Wang, Mingjin Tang, 2023. Effects of heterogeneous reaction with NO2 on ice nucleation activities of feldspar and Arizona Test Dust. J. Environ. Sci. 127, 210-221.
