| 深圳市秋季大气OH自由基总反应性测量及其构成分析 |
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| 引用本文： | 刘硕英,李歆,沈翔森,曾立民,黄晓锋,朱波,林理量,楼晟荣.深圳市秋季大气OH自由基总反应性测量及其构成分析[J].环境科学学报,2019,39(11):3600-3610. |
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| 作者姓名： | 刘硕英 李歆 沈翔森 曾立民 黄晓锋 朱波 林理量 楼晟荣 |
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| 作者单位： | 北京大学环境科学与工程学院,环境模拟与污染控制国家重点联合实验室,北京100871;北京大学深圳研究生院,环境与能源学院,城市人居环境科学与技术实验室,深圳518055;北京大学环境科学与工程学院,环境模拟与污染控制国家重点联合实验室,北京100871;上海市环境科学研究院,国家环境保护城市大气复合污染成因与防治重点实验室,上海200233;北京大学环境科学与工程学院,环境模拟与污染控制国家重点联合实验室,北京100871;南京信息工程大学,江苏省大气环境与装备技术协同创新中心,南京210044;北京大学深圳研究生院,环境与能源学院,城市人居环境科学与技术实验室,深圳518055 |
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| 基金项目： | 国家重点研发计划项目（No.2017YFC0209400）；自然科学基金青年基金（No.21407107） |
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| 摘 要： | 羟基自由基(·OH)总反应性(k_(OH))是大气中所有·OH反应物的浓度与其·OH反应速率常数乘积的总和,对k_(OH)的直接测量有助于识别未知的·OH反应物种及提升·OH收支分析的准确度.因此,本研究建立了一套基于激光光解-激光诱导荧光技术的k_(OH)在线测量系统(LP-LIF),利用紫外脉冲激光在流动管内光解臭氧产生·OH,采用激光诱导荧光技术实时测量其与采样进入流动管的活性气体反应而导致的·OH浓度衰减,通过对该衰减进行指数拟合得到采样气的k_(OH).经实验室测试,LP-LIF系统对k_(OH)的测量灵敏度为1.2 s~(-1),时间分辨率5 min.应用该系统对2018年秋季深圳地区的大气k_(OH)进行为期1个月的连续测量,结合同步观测的·OH反应物浓度数据发现,k_(OH)观测值在10～30 s~(-1)之间,主要来自一氧化碳(14%)、氮氧化物(26%)和一次排放的挥发性有机物(24%).此外,由未测量的·OH反应物贡献的k_(OH)平均约23%,且在夜间和早晚高峰时段贡献较高,推测其主要来自溶剂涂料、石化工业及LPG机动车排放.
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| 关 键 词： | OH自由基总反应性 激光诱导荧光 活性缺失 |
| 收稿时间： | 2019/3/20 0:00:00 |
| 修稿时间： | 2019/5/16 0:00:00 |
Measurement and partition analysis of atmospheric OH reactivity in autumn in Shenzhen |
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| LIU Shuoying,LI Xin,SHEN Xiangsen,ZENG Limin,HUANG Xiaofeng,ZHU Bo,LIN Liliang and LOU Shengrong.Measurement and partition analysis of atmospheric OH reactivity in autumn in Shenzhen[J].Acta Scientiae Circumstantiae,2019,39(11):3600-3610. |
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| Authors: | LIU Shuoying LI Xin SHEN Xiangsen ZENG Limin HUANG Xiaofeng ZHU Bo LIN Liliang and LOU Shengrong |
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| Institution: | 1. State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871;2. Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055,State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871,State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233,1. State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871;2. Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science&Technology, Nanjing 210044,Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055,Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055,Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055 and State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233 |
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| Abstract: | The reactivity of hydroxy radical (·OH), namely kOH, is the sum of products between the reactant concentrations and their reaction rate constants with OH for all·OH reactants in the atmosphere. Direct measurements on kOH is helpful for identifying unknown·OH reactant and for improving the accuracy of·OH budget analysis. In this study, we developed an online kOH measurement system (LP-LIF) based on laser flash photolysis-laser induced fluorescence technique. The system uses a pulsed UV laser photolyzing ozone to generate·OH radical in a flow tube. By using the laser induced fluorescence technique to record the·OH concentration decay which is caused by the reaction of·OH with the sampled reactive gases in the flow tube, and by fitting the decay curve with an exponential function, the kOH of the sample gas can be derived. The measurement sensitivity at 5 min time resolution is 1.2 s-1, determined from laboratory test experiments. The LP-LIF system was applied in a 1-month field observation campaign in Shenzhen in autumn 2018. Simultaneous measurements were performed for·OH reactants including carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), etc.. The observed kOH by LP-LIF is between 10 to 30 s-1, mainly coming from CO (14%), NOx (26%), and primarily emitted VOCs (24%). Moreover, it is found that on average around 23% kOH is from unmeasured·OH reactants. Since the contribution becomes higher during night and during morning and evening rush hours, we speculate that the missing kOH is originated from emissions of solvents, paints, petrochemical industry, and LPG vehicles. |
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| Keywords: | ·OH reactivity laser-induced fluorescence missing reactivity |
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