摘要
大气中的硝酸盐(NO_(3)^(−))是氮氧化物(NO_(x))通过与臭氧(O_(3))、羟基自由基(·OH)等多种氧化剂反应生成的关键产物,是大气中的主要污染物之一,对空气质量、气候和生态系统等产生重要影响。本文综述了海洋大气中NO_(3)^(−)的生成机制、氧化途径和氮氧同位素(如δ^(15)N、δ^(18)O)特征的全球分布,探讨了不同氧化剂(如O_(3)和·OH)在NO_(3)^(−)生成中的作用。其中,碳氢化合物/二甲基硫(hydrocarbon/dimethyl sulfate,HC/DMS)途径、N_(2)O_(5)与含氯气(Cl_(2))气溶胶的非均相反应以及NO2与活性卤素化合物反应显著影响了海洋大气中NO_(3)^(−)的生成机制并导致较高的δ^(18)O值。结合全球观测数据,发现不同海域和沿海城市NO_(3)^(−)的δ^(15)N和δ^(18)O具有显著差异,这可能反映了区域内的污染源、光化学条件及大气反应路径的差异。此外,NO_(3)^(−)会通过大气沉降进入海洋,对海洋氮循环产生影响。未来研究应加强对全球不同区域的长期监测和数据收集,完善氧化过程贡献的定量评估,从而能更系统地理解大气NO_(3)^(−)的生成机制及其对海洋生态系统和气候变化的影响。
Nitrate(NO_(3)^(−))in the atmosphere,a key product formed from nitrogen oxides(NO_(x))through reactions with multiple oxidants such as ozone(O_(3))and hydroxyl radicals(·OH),is one of the main atmospheric pollutants,impacting air quality,climate,and ecosystems.This paper reviews the formation mechanisms,oxidation pathways,and global distribution of nitrogen and oxygen isotopic(such as δ^(15)N and δ^(18)O)signatures in marine atmospheric NO_(3)^(−),focusing on the roles of various oxidants like O3 and·OH.Notably,the hydrocarbon/dimethyl sulfide(HC/DMS)pathway,the heterogeneous reaction of N2O5 with chlorine-containing(Cl_(2))aerosols,and the reaction of NO_(2) with reactive halogen compounds significantly impact the formation mechanisms of NO_(3)^(−)in the marine atmosphere and result in elevatedδ18O values.Based on global observational data,the δ^(15)N and δ^(18)O composition of NO_(3)^(−)shows significant variations across different oceanic regions and coastal cities,probably reflecting regional differences in pollution sources,photochemical conditions,and atmospheric reaction pathways.Additionally,NO_(3)^(−)deposition into marine systems affects the nitrogen cycle within the oceans.Future research should prioritize long-term monitoring and data collection across diverse global regions to enhance quantitative assessments of oxidant contributions,thereby providing a more systematic understanding of atmospheric NO_(3)^(−) formation mechanisms and their implications for marine ecosystems and climate change.
作者
陈天舒
肖红伟
关文凯
肖化云
CHEN Tianshu;XIAO Hongwei;GUAN Wenkai;XIAO Huayun(School of Agriculture and Biology,Shanghai Jiao Tong University,Shanghai 200240,China;School of Oceanography,Shanghai Jiao Tong University,Shanghai 200230,China)
出处
《热带海洋学报》
北大核心
2025年第3期167-178,共12页
Journal of Tropical Oceanography
基金
国家重点研发计划(2023YFF0806001)
国家自然科学基金项目(42373083)。
