摘要
对流层臭氧(O_(3))主要由氮氧化物(NOx)和挥发性有机物(VOCs)经过一系列光化学反应生成,反应过程呈现复杂的非线性关系.为深入了解O_(3)的光化学特征及生成机制,利用2018年夏季大气O_(3)与VOCs的观测数据,结合大气零维框架模拟模型F0AM-MCM,研究O_(3)超标日和非O_(3)超标日的O_(3)光化学特征之间的差异性.观测结果表明,O_(3)超标日期间φ(O_(3))和φ(TVOCs)的平均值分别为47.8×10^(-9)和49.0×10^(-9),为非O_(3)超标日期间O_(3)(26×10^(-9))和TVOCs(30×10^(-9))体积分数的1.8倍和1.6倍.使用F0AM模型,借助EKMA曲线和RIR分析等识别O_(3)敏感性,发现南京市O_(3)超标日和非O_(3)超标日O_(3)的形成均主要受VOCs和NOx的协同控制.F0AM-MCM模拟结果表明,在O_(3)超标日,·OH和HO_(2)的日平均混合比分别是非O_(3)超标日的1.3倍和1.8倍,表明O_(3)超标日期间具有更强的大气氧化能力,且·OH和HO_(2)的形成和损失速率也有明显的增加,表明自由基循环的增强.此外,O_(3)超标日的O_(3)生成速率明显高于非O_(3)超标日,从而导致了O_(3)超标日的O_(3)净生成速率明显高于非O_(3)超标日.以上发现提高了对南京夏季O_(3)超标日大气O_(3)光化学特征的认识.
Tropospheric ozone(O_(3))is mainly produced through a series of photochemical reactions of nitrogen oxides(NOx)and volatile organic compounds(VOCs).The reaction process presents complex non-linear relationships.In this work,datasets of atmospheric ozone and volatile organic compounds(VOCs)observed during the summer of 2018 in Nanjing were used.Combining with the framework for 0-D atmospheric model-master chemical mechanism(F0AM-MCM),the characteristics of photochemical reactions for ozone(O_(3))formation in Nanjing during the O_(3) episode days and non-episode days were investigated.The results showed thatφ(O_(3))andφ(TVOCs)in the O_(3) episode days were 47.8×10^(-9) and 49.0×10^(-9),respectively,exceeding those in the non-episode days by factors of 1.8 and 1.6.Furthermore,F0AM,the empirical kinetic modeling approach(EKMA),and relative incremental reactivity(RIR)were utilized for the calculation of ozone chemical sensitivity.It was found that O_(3) formation in Nanjing was attributed to both VOCs and NOx limitation.In addition,the modeled·OH and HO_(2) concentrations in the O_(3) episode days were 1.3 and 1.8 times higher than those in the non-episode days.The higher formation and loss rates of·OH and HO_(2) were also found during O_(3) episode days.These findings reflected that the enhancements of atmospheric oxidation capacity resulted in increased production rates of O_(3),providing an explanation for the enhancements of O_(3) concentrations in Nanjing during the O_(3) episode days.The findings also improved the understanding of the O_(3) photochemical characteristics over Nanjing in the summer during the O_(3) episode days.
作者
罗丽彤
章炎麟
林煜棋
Ahsan Mozaffar
曹梦瑶
LUO Li-tong;ZHANG Yan-lin;LIN Yu-qi;Ahsan Mozaffar;CAO Meng-yao(School of Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,China;Atmospheric Environment Center,Joint Laboratory forInternational Cooperation on Climate and Environmental Change Ministry of Education(ILCEC),Nanjing University of Information Science&Technology,Nanjing 210044,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2024年第3期1382-1391,共10页
Environmental Science
基金
国家自然科学基金项目(42192512,41977305,42150410379)。
