基于开径式非相干宽带腔增强吸收光谱大气中HONO探测方法的研究

As an important source of atmospheric hydroxyl radicals (OH), Nitrous acid (HONO) attracts much attention of the scientific community.The research of detection methods of small-scale atmospheric trace gases HONO with high sensitivity, high accuracy and high spatial and temporal resolution, is very important for the in-depth understanding of atmospheric photochemistry process. Due to different limitations of currently available methods, there are much uncertainty in the HONO concentrations measured in the field, which leads to considerable lack of atmospheric HONO data in different environments. This project intends to work on the real-time online HONO detection technology, employs a new open path style incoherent broadband cavity enhanced absorption spectroscopy method to detect both HONO and NO2 in the atmosphere, takes full account of the impact of atmospheric aerosols, turbulence on measurement of HONO in open-path mode, and studies inherent calibration of multi-component trace gas concentrations. The researches of this project are expected to improve real-time inversion algorithm model for the multi-component trace gas concentrations,increase measurement sensitivity to ten times and accuracy to two times for both HONO and NO2 as compared to current study, achieve real-time detection system with high sensitivity and high precision, meet the requirement of performing measurement at real atmosphere during daytime and nighttime, and provide accurate experimental data for further study of atmospheric chemistry process and atmospheric chemistry model to different weather patterns and trace gas budgets.

亚硝酸（HONO）作为大气中氢氧自由基（OH）的一个重要来源而倍受科学界的关注，开展小尺度大气痕量气体HONO高灵敏度、高精度和高时空分辨率探测方法的研究，对于深入理解大气光化学过程具有重要的意义。目前可行的HONO测量方法由于各种限制导致HONO的实际外场测量结果具有不确定性，不同环境下大气中HONO的数据相当缺乏。本课题拟开展HONO实时在线探测技术的研究，采用新颖的开放路径式非相干宽带腔增强吸收光谱同时探测大气中的HONO和NO2；充分考虑大气中气溶胶、湍流等对HONO开径式测量的影响；研究多组分痕量气体浓度自校正的方法，完善多组分痕量气体浓度实时反演算法模型；在现有研究基础上将HONO和NO2的测量灵敏度提高十倍，精度提高一倍，实现高灵敏度和高精度的实时探测系统，满足实际大气昼夜测量的需要，为进一步研究大气化学过程以及建立不同气象模式和痕量气体收支的大气化学模型提供准确的实验数据。

针对目前可行的HONO的测量方法由于各种限制导致HONO的实际外场测量结果具有不确定性，不同环境下大气中HONO的数据相当缺乏的突出问题和困难，本项目采用新颖的非相干宽带腔增强吸收光谱技术，充分利用非相干宽带腔增强吸收光谱的选择性强，灵敏度高的突出特点，在国内外首次建立了基于开径式非相干宽带腔增强吸收光谱系统测量实际大气中HONO和NO2，研究了大气中气溶胶、湍流等对HONO开径式测量的影响，研究了多组分痕量气体浓度自校正的方法，实现了实验室内空气中HONO的测量，HONO和NO2的测量灵敏度分别为430pptv和1ppbv，测量准确度分别为9%和10%，在理论和实验基础上分析了基于开腔式非相干宽带腔增强测量HONO与NO2的技术被应用于外场测量的可能性；在前期研究基础上建立了基于闭腔模式的非相干宽带腔增强大气HONO和NO2的测量装置，HONO和NO2的测量灵敏度分别为~300pptv和~1ppbv，准确度分别为13%和8%，测量精度为5%，能够满足HONO和NO2外场测量的需要；在国内外首次开展了基于非相干宽带腔增强吸收光谱的HOHO连续外场观测实验，并与商业可行的分析仪器进行比较，测试和验证了发展的非相干宽带腔增强吸收光谱HONO和NO2测量系统的可靠性和稳定性，同时分析了HONO和NO2在观测期间的浓度变化规律，结合NOx分析仪、O3分析仪、SO2分析仪、CO分析仪以及气象参数测量仪的数据，分析了HONO的可能来源。.在项目的资助下将非相干宽带腔增强吸收光谱技术拓展到大气重要自由基NO3的研究领域。建立了基于非相干宽带腔增强吸收光谱的NO3和NO2测量系统，测量了烟雾腔内NO2 + O3→NO3+O2反应时NO3、NO2和O3的浓度变化；结合PTR-MS装置，测量了烟雾腔NO3+Propanal和NO3+Isoprene的反应；研究了不同浓度的水汽对NO3和NO2浓度反演的影响，进一步完善了NO3和NO2浓度反演算法。

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