区域传输对庐山雾水硝酸盐组分来源和形成机制的影响  

Effects of Regional Transport for the Sources and Formation Mechanism of Nitrate Components in Mount Lu Fog Water

作　　者：李翰宇 章炎麟[1,2] 俞浩然 赵祝钰 范美益 曹芳[1,2] 张奕 吴长流 LI Hanyu;ZHANG Yanlin;YU Haoran;ZHAO Zhuyu;FAN Meiyi;CAO Fang;ZHANG Yi;WU Changliu(School of Ecology and Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,China;International Joint Laboratory on Climate and Environment Change(ILCEC),Yale-NUIST Center on Atmospheric Environment,Nanjing 210044,China)

机构地区：[1]南京信息工程大学生态与应用气象学院,南京210044 [2]南京信息工程大学生态与应用气象学院,气候与环境变化国际合作联合实验室,耶鲁大学-南京信息工程大学大气环境中心,南京210044

出　　处：《地球与环境》2024年第6期695-704,共10页Earth and Environment

基　　金：国家杰出青年科学基金项目(42325304);国家自然科学基金青年科学基金项目(42207136)。

摘　　要：雾沉降是大气气溶胶重要的汇,近年来硝酸盐已经成为雾水中重要的组成成分,厘清雾水清除的硝酸盐来源及其形成机制显得更加重要。本研究于2016年1月使用三级分档雾水采样器对庐山冬季一次大雾过程进行雾水样品的采集,并对其水溶性离子组成和硝酸盐的氮氧同位素(δ^(15)N、Δ^(17)O)进行分析。分析结果表明,硝酸盐是庐山雾水的关键离子组分(27.8%±3.1%),且在不同粒径雾滴中占比相似。不同粒径雾水(S1:≥22μm,S2:16~22μm,S3:4~16μm)硝酸盐的氧同位素异常值(Δ^(17)O-NO_(3)^(–))分别为27.3‰±1.4‰、27.8‰±1.2‰、27.7‰±1.5‰,氮同位素值(δ^(15)N-NO_(3)^(–))分别为1.2‰±2.3‰、−2.5‰±2.2‰、−2.8‰±2.8‰。通过结合氮氧同位素和贝叶斯混合模型,对庐山雾水中硝酸盐的来源和形成机制进行定量解析。模型计算结果揭示在雾中过程,庐山雾水硝酸盐的主要生成机制是N_(2)O_(5)水解反应(42%~46%),硝酸盐主要来源为机动车排放(56%±6%)。雾消散过程中,雾水硝酸盐Δ^(17)O和δ^(15)N呈现低值(δ^(15)N-NO_(3)^(–):−25.9‰,Δ^(17)O-NO_(3)^(–):24.9‰),表明微生物氮循环为雾水硝酸盐的主要来源(44.5%),且NO_(2)+·OH途径的占比上升至30%;后向气团轨迹表明,硝酸盐来源及生成机制的改变是颗粒物的传输由远距离输送(~80%)转变为本地生成主导(60%)所致。Fog deposition is an important sink for atmospheric aerosols,in recent years nitrate has become an important component of fog water,clarifying the source of nitrate that removed from fog water and the formation mechanism of nitrate becomes more important.In this study,we collected fog water samples from a winter fog process at Mount Lu in January 2016 using a three-stage fog water sampler and analyzed their water-soluble ion composition and nitrate with nitrogen and oxygen isotope(δ^(15)N,Δ^(17)O).The analytical results showed that nitrate was the key ionic component(27.8%±3.1%)of the fog water at Mount Lu,and it accounted for a similar proportion of the fog droplets in different particle sizes.The oxygen isotope anomalies of nitrate(Δ^(17)O-NO_(3)^(–))in fog water of different grain sizes(S1:≥22μm;S2:16-22μm;S3:4-16μm)were 27.3‰±1.4‰,27.8‰±1.2‰,and 27.7‰±1.5‰,respectively,and its nitrogen isotope values(δ^(15)N-NO_(3)^(–))were 1.2‰±2.3‰,-2.5‰±2.2‰,and-2.8‰±2.8‰,respectively.By combining nitrogen and oxygen isotopes and Bayesian mixing modeling,the sources and formation mechanisms of nitrate in Mount Lu fog water were quantitatively analyzed.Model calculations reveal that in the fog process,the main generation mechanism of nitrate in Mount Lushan fog water is N_(2)O_(5) hydrolysis reaction(contribution of 42%-46%),and the main source of nitrate was vehicle emission(contribution of 56%±6%);moreover,no significant differences were found in the source composition and generation pathways of nitrate in fog droplets of different particle sizes(P˃0.05).During fog dissipation,fog water nitrateΔ^(17)O andδ^(15)N showed low values(δ^(15)N-NO_(3)^(–):-25.9‰,Δ^(17)O-NO_(3)^(–):24.9‰),suggesting that microbial nitrogen cycling was the main source of nitrate in the fog water(44.5%),and that the share of NO_(2)+·OH pathway increased(17%in the fog rose to 30%in the fog dissipation phase),and the backward air mass trajectories suggest that the change in the nitrate source

关 键 词：雾水 硝酸盐 稳定氮氧同位素示踪 区域传输 

分 类 号：X513[环境科学与工程—环境工程]