大气过氧化氢观测及生成途径的模拟研究  

Observation and modeling on the production of atmospheric hydrogen peroxide

作　　者：崔亚茹 郭佳 张逸[1,2] 张晓山 Yaru CUI;Jia GUO;Yi ZHANG;Xiaoshan ZHANG(State Key Laboratory of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China;University of Chinese Academy of Sciences,Beijing,100049,China)

机构地区：[1]城市与区域生态国家重点实验室,中国科学院生态环境研究中心,北京100085 [2]中国科学院大学,北京100049

出　　处：《环境化学》2021年第5期1397-1404,共8页Environmental Chemistry

基　　金：国家自然科学基金青年项目(41605093);国家重点研发计划项目(2016YFC0203200)资助.

摘　　要：大气过氧化氢是大气光化学的重要产物,在大气污染化学中起着重要的作用。为了解不同天气条件下大气过氧化氢的浓度水平及变化规律,探究不同污染状况下大气过氧化氢的主要生成和消耗途径,本研究于2018年秋季开展了北京大气过氧化氢(H_(2)O_(2))的观测。观测期间H_(2)O_(2)的平均体积浓度为(0.29±0.36)×10^(−9),H_(2)O_(2)日变化明显,日间最高峰值出现在午后15:00左右。观测期间夜间偶尔出现H_(2)O_(2)上升的现象,并常伴随O_(3)的同时上升,H_(2)O_(2)与O_(3)的夜间高值似与污染气团的区域传输有关。本研究利用气相RACM化学机理,模拟了基于实测前体物浓度下H_(2)O_(2)浓度和生成速率、不同大气气相反应途径对H_(2)O_(2)的源、汇贡献以及H_(2)O_(2)对光化学前体物变化的敏感性。模拟结果表明,气相中HO_(2)与HO_(2)自由基结合反应是H_(2)O_(2)已知生成途径中最主要源,H_(2)O_(2)干沉降为主要的H_(2)O_(2)汇。H_(2)O_(2)生成速率对光化学前体物的敏感性研究表明,烯烃对H_(2)O_(2)的生成最为敏感。与实测值相比,模式倾向于低估H_(2)O_(2)的浓度水平,研究中认为除了高NOx条件下模式中HO_(2)自由基源的缺失的原因以外,气溶胶颗粒物上H_(2)O_(2)的非均相生成也可能是大气H_(2)O_(2)的重要来源。Hydrogen peroxide is a product of atmospheric photochemistry,which plays important role in atmospheric pollution chemistry.In order to characterize the species abundance and variation pattern of atmospheric hydrogen peroxide,and to explore the dominant production and consumption pathways for hydrogen peroxide at Beijing,an observation centered on hydrogen peroxide(H_(2)O_(2))photochemistry was conducted in autumn 2018.The mixing ratio of H_(2)O_(2) was(0.29±0.36)×10^(−9).H_(2)O_(2) exhibited pronounced diurnal variation,with daytime peaks observed at about 15:00.Air mass transport occasionally resulted in high concentrations of H_(2)O_(2) and O_(3) in the night.The H_(2)O_(2) concentration,gas phase sources and sinks,as well as the sensitivity of H_(2)O_(2) to photochemical precursors were examined by a box model employing the Regional Atmospheric Chemistry Mechanism(RACM),with the precursors concentration constrained by observations.The modeling results demonstrated that the combination of HO_(2) and HO_(2) was the predominant gas phase source of H_(2)O_(2),and the dry deposition of H_(2)O_(2) was the predominant gas phase sink of H_(2)O_(2).The H_(2)O_(2) formation rate were more sensitive to alkene species increase.Comparing with the observed value,the model underestimates the concentration of H_(2)O_(2).The underestimation suggested the existence of important H_(2)O_(2) missing source in atmospheric,such as the heterogeneous formation on aerosol particles or the model’s missing source of HO_(2) radical under high NOx condition.

关 键 词：大气过氧化氢 光化学污染 大气化学箱模式 气溶胶非均相过程 

分 类 号：X515[环境科学与工程—环境工程]