大气氧化性及其对二次污染物形成的贡献  

Atmospheric oxidation capacity and its contribution to secondary pollutants formation

作　　者：王芃 朱盛强 张梦媛 邵田[2] Qi Ying 张宏亮 Peng Wang;Shengqiang Zhu;Mengyuan Zhang;Tian Shao;Qi Ying;Hongliang Zhang(Department of Atmospheric and Oceanic Sciences,Fudan University,Shanghai 200438,China;Department of Environmental Science and Engineering,Fudan University,Shanghai 200438,China;Zachry Department of Civil Engineering,Texas A&M University,College Station TX 77843,USA;Institute of Eco-Chongming,Shanghai 200062,China)

机构地区：[1]复旦大学大气与海洋科学系,上海200438 [2]复旦大学环境科学与工程系,上海200438 [3]Zachry Department of Civil Engineering,Texas A&M University,College Station TX 77843,USA [4]崇明生态研究院,上海200062

出　　处：《科学通报》2022年第18期2069-2078,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(42077194)和国家自然科学基金国际(地区)合作与交流项目(42061134008)资助。

摘　　要：大气氧化性(atmospheric oxidation capacity,AOC)是指大气化学过程对一次污染物的氧化能力,一般用氧化剂的浓度或者总反应速率来表征.AOC对二次污染的形成起重要的作用,是研究二次污染物的重要指标.本研究利用三维空气质量模式(Community Multi-scale Air Quality model,CMAQ)模拟了2013和2020年我国主要大气氧化剂(HO_(2)、OH和NO_(3)自由基)与二次污染物(臭氧和二次颗粒物)及其前体物,并结合观测数据,综合讨论了AOC对二次污染物生成的作用.结果表明,从2013~2020年,颗粒物浓度显著下降,而AOC水平并未明显降低,甚至在华北平原(NCP)和珠江三角洲(PRD)地区还略有上升.主要氧化剂浓度呈现一定的区域特征,HO_(x)(OH+HO_(2))在四川盆地浓度水平较高,而NO_(3)自由基在华北平原的浓度水平较高.O_(3)光解过程是生成AOC最主要的来源,而OH自由基和二氧化氮生成硝酸的过程是AOC最主要的汇.AOC与二次污染物浓度关系密切,在O_(3)重污染情况下,AOC的浓度水平与年均值相比增幅明显(最高可达475%);同时,在高AOC水平下,二次有机气溶胶(secondary organic aerosol,SOA)的浓度也有显著升高.因为二次无机气溶胶(secondary inorganic aerosol,SIA)的生成过程包含气相和其他相位过程,并且受排放的季节性变化影响较大,因此总浓度与AOC关系不直接.此外,通过情景模拟分析了AOC和二次污染物浓度对不同污染物减排的响应.在夏季,减少氮氧化物(NO_(x))排放可以降低AOC,而在冬季AOC对排放调整的响应较为复杂,呈现较强的区域差异性特征.研究表明,在减少一次排放的同时要控制AOC的升高,才能高效地实现空气质量的提升和细颗粒物(PM_(2.5))与O_(3)协同控制的目标.Atmospheric oxidation capacity(AOC)is defined as the oxidation reaction rates of primary pollutants in the atmospheric chemical process,which is characterized by the oxidants concentration or the reaction rates.Atmospheric oxidation plays an important role in the formation of secondary pollutants,and works as an important indicator for the study of secondary pollution.Since 2013,the Chinese Government implemented unprecedented strident regulations to improve air quality.Although the overall levels of fine particulate matter(PM_(2.5))have dropped considerably throughout China,it remains unclear how secondary pollutants have responded to the emission reductions in view of complex gas-precursor relationship and gas-particle interactions.Previous studies also reported the positive correlation between the AOC level and secondary pollutant concentrations.The updated Community Multi-scale Air Quality(CMAQ)model with the SAPRC 11 photochemical mechanism as well as the observation data was applied in this study to investigate the relationship of the secondary pollutants(ozone and secondary aerosols)and their precursors with the major oxidants(HO_(2),OH and NO_(3) radicals)in years 2013 and 2020 in China.And the process analysis tool was implemented in the CMAQ model to determine the key oxidants budget,which could better understand the primary sources and sinks of these oxidants.This analysis was able to calculate the chemical reaction rates at each integration time step.Radical source reactions were generally photolysis reactions,and the sink reactions removed radicals through the formation of stable products.The anthropogenic emissions were from Multiresolution Emission Inventory for China(MEIC)database,and the biogenic emissions were calculated from the Model of Emissions of Gas and Aerosols from Nature(MEGAN).The meteorology inputs were generated from the Weather Research and Forecasting(WRF)model.The CMAQ model predictions agree well with the observations,with most of the model performance within the criteria.The res

关 键 词：大气氧化性 二次污染物 三维空气质量模式 臭氧 减排政策 

分 类 号：X51[环境科学与工程—环境工程]