基于氮同位素的珠三角典型地区大气PM_(2.5)中NH_(4)^(+)来源解析  

Source Apportionment of Ammonium in Atmospheric PM_(2.5) in the Pearl River Delta Based on Nitrogen Isotope

作　　者：江明 张子洋 李婷婷 林勃机 张正恩 廖彤 袁鸾 潘苏红 李军[2] 张干[2] JIANG Ming;ZHANG Ziyang;LI Tingting;LIN Boji;ZHANG Zhengen;LIAO Tong;YUAN Luan;PAN Suhong;LI Jun;ZHANG Gan(National Key Laboratory for Regional Air Quality Monitoring of Environmental Protection/Guangdong Ecological Environment Monitoring Center,Guangzhou 510308,P.R.China;State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,P.R.China;Institute of Eco-environmental and Soil Sciences,Guangdong Academy of Sciences,Guangzhou 510650,P.R.China)

机构地区：[1]国家环境保护区域空气质量监测重点实验室/广东省生态环境监测中心,广东广州510308 [2]有机地球化学国家重点实验室,中国科学院广州地球化学研究所,广东广州510640 [3]广东省科学院生态环境与土壤研究所,广东广州5106501

出　　处：《生态环境学报》2022年第9期1840-1848,共9页Ecology and Environmental Sciences

基　　金：广东省重点领域研发计划项目(2020B1111360003);国家自然科学基金项目(41977177)。

摘　　要：铵根离子(NH_(4)^(+))可促进颗粒形成和吸湿长大,是雾霾颗粒(PM_(2.5))的重要组分,但其源贡献尚不清楚。准确解析大气NH_(4)^(+)来源存在一定挑战。最近,基于NH_(4)^(+)氮同位素(δ^(15)N)的源解析方法被广泛应用到大气NH_(4)^(+)来源解析。以珠三角鹤山大气超级站为研究地点,开展为期1年的大气PM_(2.5)样品采集,选取了53个大气PM_(2.5)样品,在分析了水溶性离子、有机碳、元素碳和无机元素的基础上,测试了NH_(4)^(+)的δ^(15)N值。结果表明,鹤山站大气NH_(4)^(+)年均质量浓度为(3.39±2.21)μg·m^(−3),范围为0.07—10.9μg·m^(−3)。NH_(4)^(+)与阴离子物质的量比结果显示鹤山地区为富铵状态,且随机森林模型结果表明,NH_(4)^(+)对于鹤山地区PM_(2.5)的生成具有重要影响。大气颗粒物δ^(15)N-NH_(4)^(+)范围为−14.55‰—18.82‰,其中冬季δ^(15)N-NH_(4)^(+)变化最大(−13.27‰—18.82‰),夏季δ^(15)N-NH_(4)^(+)变化最小(−2.32‰—10.94‰)。贝叶斯源解析结果显示,农业源(畜牧和施肥)和非农业源(生物质燃烧、煤燃烧、机动车排放和废弃物)对大气NH3的年均贡献分别为36.26%和63.74%。在冬季重污染天时(2021年1月6日、1月12日和1月18日),NH_(4)^(+)浓度达全年峰值的同时,非农业源排放占比也达全年最高水平,最高达90.80%,其中机动车排放是非污染天的2—4倍,显示化石燃料燃烧是导致冬季污染事件的重要原因。基于同位素源解析方法所得非农业源NH3排放贡献约为源清单方法所得结果的7倍,源清单法可能严重低估了机动车等重要非农业源的排放贡献。为了进一步改善珠三角地区空气质量,需要重视非农业源NH3的排放。Ammonium(NH_(4)^(+))could promote particle formation and hygroscopic growth and is an important component of fine particles(PM_(2.5)),but its source contribution is still unclear.There are some challenges in accurately analyzing the source of atmospheric NH_(4)^(+).In recent years,the source apportionment method based on nitrogen isotope has been widely applied to the source apportionment of atmospheric NH_(4)^(+).In this study,Heshan atmospheric super-station in the Pearl River Delta was selected as the research site to carry out a one-year collection of atmospheric PM_(2.5) samples.A total of 53 atmospheric PM_(2.5) samples were selected.Based on the analysis of water-soluble ions,organic carbon,elemental carbon and inorganic elements,theδ^(15)N value of ammonium was tested.The results showed that the annual average concentration of ammonium at Heshan station was(3.39±2.21)μg·m^(−3),ranging from 0.07 to 10.9μg·m^(−3).The results of the molar ratio of ammonium to anions showed that Heshan region was rich in ammonium,and the results of random forest model showed that NH_(4)^(+)had an important effect on the formation of PM_(2.5) in Heshan region.Theδ^(15)N-NH_(4)^(+)value in atmospheric particulate matter ranged from−14.55‰to 18.82‰,with the largest variation in winter(−13.27‰–18.82‰)and the smallest variation in summer(−2.32‰–10.94‰).The source apportionment results analyzed by Bayesian model showed that the average annual contributions of agricultural sources(livestock and fertilizer)and non-agricultural sources(biomass combustion,coal combustion,vehicle emissions and waste)to atmospheric NH_(3) were 36.26%and 63.74%respectively.During the heavily polluted days in winter(January 6,January 12 and January 18,2021),while the NH_(4)^(+)concentration reached the peak of the whole year,the proportion of non-agricultural source emissions also reached the highest level of the whole year,up to 90.80%.Among them,the emission of vehicles was 2–4 times that of the clean days,indicating th

关 键 词：珠三角 鹤山大气超级站 PM_(2.5) 铵根离子(NH4+) 氮同位素 源解析 

分 类 号：Q948[生物学—植物学] X16[环境科学与工程—环境科学]