摘要
野火是大气颗粒物的重要来源,并通过大气输送对区域大气环境产生重要影响。本研究于2022年6—9月在特大城市莫斯科背景点采集PM_(10)样品,期间距城市200 km的梁赞森林发生野火。通过分析碳质组分(有机碳OC、元素碳EC)和水溶性无机离子(WSIIs)的浓度变化,评估野火对PM_(10)组成的影响。结合后向轨迹和火点图,确定8月发生的两次PM_(10)浓度显著升高的污染事件(事件1和事件2)受到野火烟羽的影响。事件1和事件2期间,PM_(10)均值分别为(44.1±7.2)和(71.0±19.2)μg/m^(3),是城市背景期间的1.9倍和3.0倍,且夜间PM_(10)浓度高于白天。与城市背景期相比,OC和EC浓度均有显著增高,有机物(OM)在PM_(10)中的占比在事件1和事件2中分别升至68.3%和73.2%。SOC浓度在事件1和事件2中分别较城市背景期间(3.9±1.9μg/m^(3))上升2.0和4.8倍,且SOC占OC的比重升至60%以上。野火烟羽传输的影响增加了OM,尤其是SOC在PM_(10)中的比重。WSIIs浓度在事件1和事件2中分别为城市背景期间(1.5±0.9μg/m^(3))的1.6和4.2倍,其中二次无机离子(SNA)占WSIIs的比例上升。污染事件中SNA与K+的相关性明显,且NO_(3)^(-)/SO_(4)^(2-)小于1,区别于城市背景期间(NO_(3)^(-)/SO_(4)^(2-)>1),表明污染事件中SNA受到生物质燃烧的贡献。根据氮氧化速率(NOR)和硫氧化速率(SOR)的比较,野火烟羽传输的影响促进了SO_(2)和NO_(2)向SO_(4)^(2-)和NO_(3)^(-)的转化,尤其是夜间SO_(2)的转化。
Wildfires are an important source of particulate matter in the atmosphere and have a significant impact on the regional atmospheric environment through atmospheric transportation.In this study,PM_(10) samples were collected at Moscow urban background from June to September 2022,covered the periods of wildfires occurred in the Ryazan forest,200 km from the city.Mass concentrations of carbonaceous components(organic carbon,OC,and elemental carbon,EC)and water soluble inorganic ions(WSlls)were analyzed to assess the impact of wildfires on the PM_(10) composition.Based on backward air mass trajectories and fire spot maps analysis,the two pollution events with significantly increased PM_(10) concentrations(Plume 1 and Plume 2)that occurred in August were identified.During Plume 1 and Plume 2,averaged PM_(10) were 44.1±7.2 and 71.0±19.2μg/m^(3),respectively,1.9 and 3.0 times higher than during urban background period,nighttime PM_(10) concentrations were higher than daytime.SOC concentrations increased by 2.0 and 4.8 times,respectively,compared to urban background(3.9±1.9μg/m^(3)).OC and EC concentrations(Plume 1:18.8±7.0 and 3.9±1.2μg/m^(3);Plume 2:32.5±15.1 and 5.4±2.4μg/m^(3))were significantly higher than those during urban background period(7.7±2.8 and 2.1±1.0μg/m^(3)).Proportion of organic matter(OM)in PM_(10) and SOC in OC increased to 68.3%and 73.2%and up to more than 60%.The influence of the transportation of wildfire plumes increased the proportion of OM,especially SOC.The total concentrations of WSlls during Plume 1 and Plume 2 increased by 1.6 and 4.2 times compared to urban background(1.5±0.9μg/m^(3)),and the proportion of secondary inorganic ions(SNA)in WSlls also increased.Under plumes impact,significant correlations between SNA and K+were found,and NO_(3)^(-)/SO_(4)^(2-)were less than 1,different from urban background(NO_(3)^(-)/SO_(4)^(2-)>1),indicating that SNA contributed by wildfire smoke.By comparison of nitrogen oxidation(NOR)and sulfur oxidation(SOR)rates,it indicated the promotion of the conversions of SO_(2) and NO_(2) to SO_(4)^(2-)and NO_(3)^(-)as a result of wildfire smoke plumes transportation to the megacity,especially the conversion of SO_(2) at night.
作者
黄泽亮
曹芳
Olga B.Popovicheva
杨笑影
Roman G.Kovach
Nikolay S.Kasimov
谢锋
吴长流
章炎麟
HUANG Zeliang;CAO Fang;Olga B.Popovicheva;YANG Xiaoying;Roman G.Kovach;Nikolay S.Kasimov;XIE Feng;WU Changliu;ZHANG Yanlin(School of Ecology and Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China;International Joint Laboratory on Climate and Environment Change(ILCEC),Yale-NUIST Center on Atmospheric Environment,Nanjing 210044,China;Skobeltsyn Institute of Nuclear Physics,Lomonosov Moscow State University,Moscow 119991,Russia;Faculty of Geography,Lomonosov Moscow State University,Moscow 119991,Russia)
出处
《地球与环境》
北大核心
2025年第6期761-772,共12页
Earth and Environment
基金
国家自然科学基金项目(42192512)
俄罗斯科学基金会项目(19-77-30004-П)。
