2025年5月6日 9:36 星期二
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大气中气态氨的采集分析及氮同位素源解析综述

  • 刘刚1

    机 构：

    1. 1.南京信息工程大学环境科学与工程学院,南京, 210044

    ×

1.南京信息工程大学环境科学与工程学院,南京, 210044；

Review on ammonia in ambient air:sampling,measurement and source apportionment via nitrogen isotopes

  • LIU Gang1

    Affiliation：

    1. 1.School of Environmental Science and Engineering,Nanjing University of Information Science & Technology,Nanjing 210044 ,China

    ×

1.School of Environmental Science and Engineering,Nanjing University of Information Science & Technology,Nanjing 210044 ,China；

作者简介:

刘刚,男,博士,教授,主要从事大气污染物组成和源示踪研究．Liugang650104@sina.com

中图分类号:X513

文献标识码:A

DOI:10.13878/j.cnki.jnuist.20220216001

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目录contents

    摘要

    氨是大气中生成PM2.5的主要前驱物之一．为了用同位素方法更精确地识别大气中氨的来源,减轻城市大气PM2.5污染,对近年来国内外有关气态氨的采样与浓度分析方法、氮同位素比值测定和估算方法、不同来源氨的氮同位素组成及同位素分馏、大气中氨的氮同位素组成及分馏、大气颗粒物和降水中NH+4的氮同位素组成,以及大气中氨的源解析等研究现状进行了分析．据此为未来的研究工作提出了若干建议:被动采样法会引起NH3的氮同位素分馏,采样前应确定最低采样质量;需加强对生物质燃烧、天然土壤、海洋、污水处理厂、植物及其他潜在排放源氨的氮同位素组成研究;要进一步研究不同排放源氨的氮同位素组成变化机理;应以更高的时间分辨率同时测定气态NH3和颗粒态NH+4的质量浓度和氮同位素组成,以探讨颗粒态NH+4生成过程中氮的同位素分馏机理;需更加深入地研究不同大气污染状况和气象条件下气态氨的氮同位素分馏机理．

    Abstract

    Gaseous ammonia (NH3) is a key precursor in the formation of PM2.5 in the atmosphere.To enhance the precision of identifying NH3 sources through isotopic techniques and alleviate urban air PM2.5 pollution,this paper reviews recent researches on the following aspects:methods for sampling and quantifying gaseous NH3,techniques for determining or estimating its nitrogen isotope ratios,the nitrogen isotope compositions and fractionations of NH3 in air and emitted from diverse sources,the isotopic compositions of NH+4 in atmospheric particulate matter and rainfall,as well as the source apportionment of atmospheric NH3.Several recommendations for future research are accordingly proposed.The minimum amount of samples should be determined before collecting air samples with passive method considering nitrogen isotope fractionation of NH3.It is necessary to clarify the nitrogen isotope compositions of ammonia from biomass combustion,natural soils,oceans,sewage plants,vegetation,and other potential sources.The nitrogen isotopic variation mechanism for ammonia from diverse sources needs to be further investigated.Both mass concentrations and isotopic compositions of gaseous NH3 and particulate NH+4 should be measured simultaneously with higher temporal resolution to explore the mechanism of nitrogen isotope fractionation during the formation of particulate NH+4.Additionally,exploring the isotopic fractionation of gaseous NH3 under diverse meteorological conditions and air pollution status is recommended.

    关键词

    大气 ； 氨 ； 氮同位素 ； 源解析

  • 0 引言

  • 铵盐是大气中PM2.5的主要组分之一，灰霾天气时其对PM2.5的质量贡献率达30%~77% [1]．空气中的氨气与二氧化氮、二氧化硫等酸性气体反应可生成相应的铵盐．据估算，2006年中国的氨排放量约为98 亿kg[2]．减少污染源向大气中排放氨气，能够降低颗粒态铵盐的浓度，进而改善城市的环境空气质量．大气中的氨有多种来源，牲畜养殖和氮肥施用等农业活动是最大的人为排放源[3]．此外，人类粪便、化石燃料和生物质的燃烧过程、天然土壤、海洋等也均向大气中排放氨[4-6]，但在不同地区各种排放源对大气氨的贡献是有差别的[7-9]．总体而言，不同来源氨的氮同位素比值（δ15N）存在明显的差别[4，10-12]．利用大气中氨的氮同位素组成进行源解析，是目前追踪其来源的较为有效的方法[13-18]．Pan 等[19]对大气氨浓度的观测现状、被动采样器的氨采样效率及其氮同位素测定值的偏差进行了综述，并将之前用被动采样器所采集大气氨的氮同位素测定值进行校正后，重新对北京的大气氨进行源解析，指出由于普遍使用不同品牌的被动采样器采样，并且对测定值不加校正地使用，会导致大气氨浓度观测结果和源解析结果产生较大的偏差．为了更准确地识别氨的来源，本文对大气氨的采样方法、浓度和氮同位素分析方法、δ15N值估算方法、不同来源氨的氮同位素组成及同位素分馏、大气中氨的氮同位素组成及同位素分馏、大气中NH+4的氮同位素组成、大气中氨气的源解析等方面的研究现状进行综述，并就有关问题开展进一步研究提出了若干建议．

  • 1 样品采集和分析

  • 1.1 采样方法

  • 大气中氨气的浓度很低，在中国典型农业区大气中氨气的质量浓度为1~23.9 μg·m-3[20]，在厦门市空气中的平均质量浓度为7.9 μg·m-3[21]，在西安市夏季空气中的平均质量浓度为38.0 μg·m-3[22]．为了采集足够数量的氨气以满足氮同位素比值测定的需要，主要使用被动采样器进行数天时间的采样．目前有多个品牌的被动采样器可供选用，它们具有相似的采样原理[11，18，20]．适应型低成本高吸收被动采样器（ALPHA）为一只一端开口的圆形聚乙烯瓶（高26 mm、直径27 mm）．该瓶内装有2~3张滤膜．第1张为聚四氟乙烯膜，用以除去空气中的颗粒物和扩散氨气．另外2张为石英滤膜（直径25 mm）．滤膜上均浸渍了质量分数为2%的磷酸甲醇溶液，用以吸收氨气，使之与磷酸反应生成铵离子．Ogawa被动采样器为一支长3 cm、直径为2 cm的圆柱形聚合物管．该采样器一端配有1个扩散盖，其后安装了1张不锈钢筛网和1~3张浸渍了磷酸的石英滤膜（直径14 mm）．采样器中安装吸收膜的多少，取决于所要采集空气中氨气的浓度．两种被动采样器的结构如图1所示．

  • 图1 被动采样器结构示意

  • Fig.1 Schematic of passive samplers

  • 用主动采样法采集氨气时有两种采样器可供选用．一种是多喷嘴阶式撞击采样器（MCIs），另一种是化学蜂窝物种分类筒式采样器（CCSCs）[23]．MCIs内装4级滤膜．当空气以20 L/min的速率被抽入并穿过时就可采集其中的颗粒物和氨气．MCIs的第1级装有一个PM2.5撞击器，并用一张石英滤膜（Φ=47 mm）收集空气动力学直径大于2.5 μm的颗粒物．第2级也是一张石英滤膜（Φ=47 mm），用于捕获PM2.5．第3级是一张浸渍了碳酸钠溶液的纤维素滤膜（Φ=47 mm），用于吸收HNO3、HNO2、HCl、SO2等酸性气体．第4级是一张浸渍了柠檬酸的纤维素滤膜，用于收集氨气．CCSCs是一种玻璃材质的蜂窝状采样管-滤膜采样系统．抽入的空气（10 L/min）首先穿过涂有聚四氟乙烯的不锈钢PM2.5撞击器，气流中粒径大于2.5 μm的粗颗粒物被除去．空气流中的酸性气体和氨气然后分别被涂渍了碳酸钠溶液和柠檬酸溶液的两个蜂窝状采样管收集．气流中剩余的颗粒物穿过采样管后被收集在下方的尼龙滤膜（Φ=47 mm）上．在尼龙滤膜之后再加装一张涂渍了柠檬酸溶液的纤维素滤膜，以收集从之前所采颗粒物上挥发的氨气，或者因前面的采样管饱和而穿透的氨气．两种主动采样器的结构如图2所示．

  • 图2 主动采样器结构示意

  • Fig.2 Schematic of active samplers

  • 这两种采样器均可同时采集气态NH3和颗粒态NH+4．用MCIs和CCSCs同时采集机动车隧道内的空气样品，分析结果表明二者之间的氨气浓度测定值没有明显的差别，但MCIs对应的δ15N-NH3值（6.3±1.6‰）比CCSCs的值（4.8±2.3‰）稍大．这一微小差别（1.5±2.8‰）可能是由于采样期间CCSCs内的采样管达到饱和状态，使气态NH3和颗粒态NH+4混淆造成的．

  • 1.2 浓度分析方法

  • 用上述方法完成采样后，从采样器中用塑料镊子取出收集氨气的滤膜或蜂窝状采样管，置于10 mL聚氯乙烯等有机材质的试管中．加入5 mL去离子水（18.2 MΩ·cm），用力振摇，使之与水充分接触．将试管放入超声振荡器中振荡提取30 min后离心（3 000 r/min）2 min，将上清液用孔径为0.45 μm的亲水滤膜过滤，以测定铵离子的浓度．

  • 目前多用离子色谱法测定上述水溶液中铵离子的浓度，进而计算所采集的NH+4质量．该测定方法是一种成熟方法．不同厂商生产的离子色谱仪配置不同的阳离子分析色谱柱，其对应的淋洗液类型也不尽相同．实际测定时离子色谱柱和电导检测器保持室温，进样10或20 μL．首先分析不同浓度的NH+4标准溶液，以其浓度为横坐标、色谱峰面积为纵坐标，绘制标准曲线，建立线性回归方程，其线性回归系数r应大于0.999．然后再测定铵离子提取水溶液样品．以离子色谱峰的保留时间定性，以外标法定量．提取液的体积乘以铵离子的浓度即为所采每个样品中NH+4的总质量．

  • 对于被动采样法而言，根据采样时间、NH+4的总质量，以及被动采样器厂商提供的换算系数等参数和计算公式，就可求得所采空气中氨气的浓度．以被动采样器Analyst为例，可按下式计算空气中气态NH3的质量浓度:

  • CNH3=9.06×102×mNH4+t.
    (1)

  • 式中: CNH3 表示空气中气态NH3的质量浓度，μg·m-3; mNH4+ 为采样膜上由气态NH3转化的NH+4的质量，μg; t为采样时间，h; 9.06×102为厂商提供的换算系数．

  • 式（1）假设采样期间的平均气温（T）是20℃，否则，须对计算结果乘以校正系数293273+T1.8.

  • 与DELTA等主动采样器相比，用ALPHA、Analyst、Radiello等被动采样器采集大气中的氨气，所测NH3的质量浓度要低4%~27.5% [24-25]．具体偏低程度因被动采样器品牌而异．导致测定结果偏低的原因可能是在当时的采样环境条件下质量换算系数不准确．

  • 对于主动采样法来说，根据上述所测定NH+4的总质量可换算得到气态NH3的总质量，再根据采样时间和抽气速率，即可求得所采空气中氨气的质量浓度．

  • 1.3 氮同位素分析方法

  • 大气中气态NH3的氮同位素比值测定方法与颗粒态NH+4的完全相同．将由上述氨采样方法采集转化而来的NH+4溶于去离子水中，按前述方法提取、净化后取适量样品水溶液，用次溴酸盐在pH值为12的碱性条件下将大约40 nmol NH+4氧化为NO-2．反应30 min后加入0.4 mL亚砷酸钠溶液（0.4 mol）以除去剩余的次溴酸盐．用羟胺或叠氮化钠在强酸性条件下将NO-2定量地转化为N2O．用吹扫-捕集系统把水溶液中的N2O浓缩富集，用载气送入稳定同位素质谱计测定其氮同位素比值．每次测定至少需要60 nmol N2O[13，26-27]．测定结果以相对于空气中N2的千分比值表示:

  • δ15N=15N/14N样品 /15N/14N标准 -1×1000.

  • 用被动采样器（ALPHA、Analyst、Radiello）采集北京市区夏季大气中的氨气，虽然其δ15N测定值之间不存在显著的差别，但均明显低于用主动采样器所采样品的测定结果．其原因是在采样过程中NH3分子因扩散而发生了明显的氮同位素分馏[25]．如果用被动采样器采集的NH3少于70 μg，则其δ15N测定值比实际结果要低10‰~15‰[28]．

  • 1.4 δ15N值估算方法

  • 除了上述直接测量方法之外，还可用间接的方法估算大气中初始气态氨的δ15N值．例如，可以在测定雨水中NH+4含量及其δ15N值的基础上，根据瑞利（Rayleigh）模型估算氨气的δ15N值[16]．另外，还可以根据充分混合封闭系统中同位素质量平衡模型，按下式估算气态氨的δ15N值[29]:

  • δ15N-NH3( 气 )=δ15N-NH4 (固) )+-εNH4-NH3(1-f).
    (2)

  • 式中:δ15N-NH3（气）和δ15N-NH+4（固）分别是初始气态NH3和颗粒态NH+4的δ15N值; f是初始气态NH3转化为颗粒态NH4+.的分数（f=NH+4/（NH+4+NH3），μmol/μmol）; εNH4-NH3表示颗粒态NH+4和气态NH3之间平衡氮同位素交换分馏因子．εNH4-NH3与温度（T）之间的关系式为

  • εNH4-NH3=12.4678×1000/T-7.6694.
    (3)

  • 只要在采样的同时也测得气温，根据式（3）就可以估算不同温度下的εNH4-NH3值．另外，只要测得大气中颗粒态NH+4和气态NH3的浓度，就可求得f值．气态NH3的浓度也可以通过ISORROPIA-Ⅱ热力学模型估算．由此可见，如果测定了δ15N-NH+4（固）值，即可根据上述公式估算大气中初始NH3的δ15N值．

  • 由于目前不同温度下εNH4-NH3的实验值很少，大气中气态NH3浓度的测定结果也不多见，用式（2）估算所得δ15N-NH3（气）值的准确性有待进一步探讨．

  • 2 不同来源氨气的氮同位素组成及其同位素分馏

  • 2.1 不同来源氨气的氮同位素组成

  • 不同来源氨的δ15N值之间普遍存在差异．家畜粪尿（-56‰~-9‰）和化肥（-48‰~-36‰）所排放氨的δ15N值要低于发电厂（-14.6‰~-11.3‰）、机动车（-4.6‰~-2.2‰）和海洋（-10.2‰~-2.2‰）[10]．中国隧道内机动车排放氨的δ15N值更低（-17.8‰~-9.6‰），城市生活垃圾和人粪尿排放氨的δ15N平均值分别为-37.8‰~-29.1‰、-38.4‰~-35.6‰[11，30]．生物质燃烧所排放氨的δ15N平均值（+12.0‰）比前述污染源明显偏高[12]．在太湖地区由化肥、养猪场和奶牛场排放氨的δ15N值分别为-30.8‰~-3.3‰、-35.1‰~-10.5‰、-24.7‰~-11.3‰[31]．垃圾填埋场排放氨的δ15N值为-25.4‰[21]．显然，大多数污染源所排放氨的δ15N值均具有较大的变动范围．

  • 2.2 不同来源氨气的氮同位素分馏

  • 不同排放源在氨气的排放过程中总是要发生动力学氮同位素分馏或者平衡氮同位素分馏，从而使同种来源气态氨的氮同位素组成存在一定的差别．从家畜粪便中排放的氨气，在冬夏两季之间存在明显的同位素分馏．其δ15N值的变化范围分别为-45‰~0‰、-22‰~5‰[32]．在硫酸铵水溶液中NH3和NH+4之间会发生平衡同位素分馏．在23℃、50℃和70℃时分别达45.4‰、37.7‰和33.5‰[33]．氨从硫酸铵水溶液中高效脱气时主要发生动力学同位素分馏，其在2℃和21℃的氮同位素分馏系数分别为0.989 8和0.991 8[34]．在低效脱气条件下发生的氮同位素效应则介于动力学同位素分馏和平衡同位素分馏之间．氨从水溶液中挥发时的氮同位素分馏系数还受pH值的影响．当水溶液的pH值分别为8.5和9.2时，相应的分馏系数分别为1.019和1.030[35]．农田空气中氨的δ15N值也有一定的变化[36]．农田施用尿素后挥发氨的δ15N值为-46.0‰~-4.7‰，且随着尿素施用量的增加而变小[37]．此外，土壤的pH值及其NH+4含量，以及氨挥发速率，均显著影响挥发氨的δ15N值．

  • 2.3 大气中氨的氮同位素分馏

  • 氨气进入大气后要经历一系列物理过程和化学过程．在此过程中也会发生动力学氮同位素分馏或者平衡氮同位素分馏，从而改变了自身及其反应产物的氮同位素组成．这些过程可以是气相、液相和固相之间的平衡反应[4]:

  • 15NH3（气）+14NH3（ 液 ）→→14NH3（气）+15NH3（液）， 15NH3（ 气）+14NH4（液））+14NH3（ 气）+15NH4（液））+， 15NH3（ 气 ）+14NH4（固）+→14NH3（气）+15NH4（固）+.

  • 理论计算[38-39]和实验结果[33，40]均表明确实存在上述氮同位素交换反应，其结果使溶解态和固态NHx（NH3或NH+4）的15N/14N值大于气态NH3．大气中气态NH3和雨水中NH+4之间的氮同位素分馏系数估算值为10.4‰±4.3‰[16]．在气态氨和酸发生单向中和反应的非平衡条件下，NH3与NH+4之间发生的氮同位素分馏是动力学分馏，结果导致溶解态和固态的NH+4均富集15N[41]．前人同样发现固相或液相NH+4比气相NH3富集15N[42-45]．显然，气态NH3和颗粒态NH+4之间氮同位素组成的差异很大程度上取决于影响气体-颗粒物转化的大气条件．这些因素使定量应用NH3或NH+4的氮同位素组成进行NH3的源解析变得更加复杂．

  • 3 大气中NH+4的氮同位素组成

  • 3.1 颗粒物中NH+4的氮同位素组成

  • 大气颗粒物中NH+4的氮同位素组成受到NH3排放源类型和气象条件等因素的影响，具有较大的变化范围（-37.1‰~+17.8‰）．北京市区颗粒态NH+4的氮同位素组成在刮北风时偏轻（-33.8‰），在刮南风时偏重（0~+12.0‰）[13]; 在非灰霾天气时偏轻（-37.1‰~-21.7‰），在灰霾天气时偏重（-13.1‰~+5.8‰）[41]．在京津冀地区的城市大气颗粒物中，清洁天气的NH+4富集15N，其δ15N值为+14.6‰±2.5‰，而灰霾天气的NH+4则相对亏损15N，其δ15N值为+7.8‰±4.2‰[46]．广州市灰霾天气颗粒态NH+4的δ15N值变化很大（-6.1‰~+17.8‰）[14]．这与当地大气中NH3的多来源及其贡献变化有直接的关系．在大西洋上空的细模态粒子（空气动力学直径＜1 μm）中，高纬度地区的NH+4具有比温带和热带更小的δ15N值[47]．

  • 任何类型污染源所排放的NH3及所生成NH+4的δ15N值大小顺序均是NH3（气）＜ NH+4（液）＜NH+4（固），而且NH+4（固）和NH3（气）的δ15N值之差与温度显著负相关[15]．空气中颗粒态NH+4比气态NH3富集15N，实验结果表明，在25℃时其富集因子达+33‰[48]，而Felix等[18]对该因子在25℃时的理论推算结果为+34‰，两者十分接近．

  • 3.2 降水中NH+4的氮同位素组成

  • 大气降水中NH+4的氮同位素组成随着季节和空间而发生明显的变化，也具有较大的波动范围（-28.7‰~+35.2‰）．重庆农村和市区降水中NH+4的δ15N月平均值变化区间为-16.4‰~+35.2‰[26]．贵阳雨水中NH+4的δ15N值变化范围为-28.7‰~+6.6‰，平均为-10.6‰[49]．在中国东北林区降水中，NH+4的δ15N值在-24.6‰~+16.2‰间变化，且夏季值（平均-2.3‰）大于冬季值（平均-16.4‰）[29]．在湛江雨季降水中NH+4的δ15N值大于旱季[50]．

  • 4 大气中氨的氮同位素组成

  • 大气中气态氨的氮同位素组成也因时因地而异，其δ15N值变化范围为-42.4‰~+7.1‰．利用雨水中NH+4的氮同位素比值估算得到贵阳大气中初始氨的δ15N平均值为-16.8‰[16]．以气溶胶中NH+4的δ15N测定值估算得到北京市区大气中初始NH3的δ15N值在非霾日和霾日分别为-35‰、-14.3‰~-22.8‰ [17]，其差别大的原因是这两种天气的NH3首要排放源分别是农业源和化石燃料源．直接采集北京市区大气NH3后测得的δ15N值为-26.8‰~-17.2‰[51]，该值与前述霾日的估算值较为接近．美国大气中NH3的δ15N值在-42.4‰~+7.1‰之间变化，其平均值为-15.1± 9.7‰．农业区NH3的δ15N值偏低且具有季节性变化，而在非农业区该值较高且无季节性变化[18]．在美国柯柏斯克里斯提的城市空气中，NH3的δ15N平均值为-19.1±12.7‰[52]．

  • 5 大气中氨气的源解析

  • 通常根据大气中NH3的δ15N测定值或换算值，利用“IsoSource”“MixSIAR”“IsoError”等同位素混合模型估算不同排放源对总氨的贡献．只要将各主要排放源气态NH3的δ15N值输入混合模型中，通过反复迭代即可估算出各自的贡献．该类模型的计算依据是同位素质量平衡原理，其计算公式如下:

  • δ15N-NH3( 大气 )=∑i=1n fi×δ15N-NH3(i).
    (4)

  • 式中:δ15N-NH3（大气）和δ15N-NH3（i）分别表示大气中和排放源i所排放气态氨的δ15N值，fi表示排放源i对大气气态氨的贡献，fi的总和为1．

  • 不同城市大气中氨的主要排放源不尽相同．利用气溶胶中NH+4的δ15N值进行源解析，结果表明北京市区灰霾天气时的大气氨主要来源于化石燃料燃烧过程（90%）[13，41]，而非灰霾天气只有67%的氨来自此类排放源[46]．在2014年亚太经济合作峰会期间北京空气中的氨分别来源于机动车（8.8%）、生活垃圾（24.9%）、猪场（14.3%）和尿素（52.0%）[11]．广州灰霾天气的大气氨中有5%~80%来自非化石燃料燃烧源[14]．贵阳大气中的氨分别来自动物废弃物（22%）和化肥（22%）的挥发、机动车尾气（19%）、煤（19%）和生物质燃烧（17%）[49]．非农业源和农业源均是上海市大气中氨的重要来源[53]．在太湖地区的大气中，75%以上的氨来源于化肥挥发和家畜的排泄物[31]．厦门市大气中70%的氨来源于和化石燃料有关联的排放[21]．西安市夏冬两季空气中的氨分别有66.4%和62.5%来自非农业排放源[22]．美国柯柏斯克里斯提市大气中的氨分别来自非农业源（55%±6%）和农业源（45%±6%）[52]．

  • 6 展望

  • 通过以上现有研究成果可知，被动采样法会引起氨气的氮同位素分馏．因此，在用被动采样器采集空气样品前，需要进行室内模拟采样试验，以确定合理的氨气最低采样量．如果条件允许，最好用主动采样器采样．

  • 目前关于大气中气态氨排放源的氮同位素组成研究仍然有限，未来需要加强对生物质燃烧、天然土壤、海洋、污水处理厂、植物以及其他潜在来源氨的氮同位素组成研究．

  • 应强化不同排放源氨的氮同位素组成变化机理研究，以缩小同类型排放源的δ15N值变化范围．尤其要进一步研究pH值、湿度和温度等因素对土壤中化肥来源氨的δ15N值影响．

  • 要更深入地研究不同大气污染状况和气象条件下气态氨的氮同位素分馏机理．

  • 大气中NH3和NH+4具有不同的寿命，在同一地点的空气中二者来源可能不同．应以更高的时间分辨率同时测定气态NH3和颗粒态NH+4的质量浓度和氮同位素组成，以探讨颗粒态NH+4生成过程中氮的同位素分馏机理．

  • 在利用颗粒态NH+4的δ15N值估算初始氨的δ15N值时需要平衡氮同位素交换分馏因子εNH+4-NH3．已有实验仅验证25℃下的实验结果和理论估算结果是一致的，而其他温度条件下的估算结果并没有得到实验验证．因此，有必要进一步开展实验研究，以确定其他温度条件下εNH+4-NH3估算值的可靠性．

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    • [14] Liu J W,Ding P,Zong Z,et al.Evidence of rural and suburban sources of urban haze formation in China:a case study from the Pearl River delta region[J].Journal of Geophysical Research:Atmospheres,2018,123(9):4712-4726

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    • [17] Pan Y P,Tian S L,Liu D W,et al.Source apportionment of aerosol ammonium in an ammonia-rich atmosphere:an isotopic study of summer clean and hazy days in urban Beijing[J].Journal of Geophysical Research:Atmospheres,2018,123(10):5681-5689

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    • [19] Pan Y P,Gu M N,He Y X,et al.Revisiting the concentration observations and source apportionment of atmospheric ammonia[J].Advances in Atmospheric Sciences,2020,37(9):933-938

    • [20] Pan Y P,Tian S L,Zhao Y H,et al.Identifying ammonia hotspots in China using a national observation network[J].Environmental Science & Technology,2018,52(7):3926-3934

    • [21] Wu S P,Zhu H,Liu Z,et al.Nitrogen isotope composition of ammonium in PM2.5 in the Xiamen,China:impact of non-agricultural ammonia[J].Environmental Science and Pollution Research International,2019,26(25):25596-25608

    • [22] Wu C,Wang G H,Li J,et al.Non-agricultural sources dominate the atmospheric NH3 in Xi'an,a megacity in the semi-arid region of China[J].Science of the Total Environment,2020,722:137756

    • [23] Song L L,Walters W W,Pan Y P,et al.15N natural abundance of vehicular exhaust ammonia,quantified by active sampling techniques[J].Atmospheric Environment,2021,255:118430

    • [24] Puchalski M A,Sather M E,Walker J T,et al.Passive ammonia monitoring in the United States:comparing three different sampling devices[J].Journal of Environmental Monitoring:JEM,2011,13(11):3156-3167

    • [25] Pan Y P,Gu M N,Song L L,et al.Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia[J].Atmospheric Research,2020,243:105018

    • [26] Leng Q M,Cui J,Zhou F W,et al.Wet-only deposition of atmospheric inorganic nitrogen and associated isotopic characteristics in a typical mountain area,southwestern China[J].Science of the Total Environment,2018,616/617:55-63

    • [27] Smirnoff A,Savard M M,Vet R,et al.Nitrogen and triple oxygen isotopes in near-road air samples using chemical conversion and thermal decomposition[J].Rapid Communications in Mass Spectrometry,2012,26(23):2791-2804

    • [28] Kawashima H,Ogata R,Gunji T.Laboratory-based validation of a passive sampler for determination of the nitrogen stable isotope ratio of ammonia gas[J].Atmospheric Environment,2021,245:118009

    • [29] Huang S N,Elliott E M,Felix J D,et al.Seasonal pattern of ammonium 15N natural abundance in precipitation at a rural forested site and implications for NH3 source partitioning[J].Environmental Pollution,2019,247:541-549

    • [30] Shao S C,Zhang Y L,Chang Y H,et al.Online characterization of a large but overlooked human excreta source of ammonia in China's urban atmosphere[J].Atmospheric Environment,2020,230:117459

    • [31] Ti C P,Gao B,Luo Y X,et al.Isotopic characterization of NHx-N in deposition and major emission sources[J].Biogeochemistry,2018,138(1):85-102

    • [32] Buzek F,Cejkova B,Hellebrandova L,et al.Isotope composition of NH3,NOx and SO2 air pollution in the Moravia-Silesian region,Czech Republic[J].Atmospheric Pollution Research,2017,8(2):221-232

    • [33] Li L,Lollar B S,Li H,et al.Ammonium stability and nitrogen isotope fractionations for NH+4-NH3(aq)-NH3(gas)systems at 20-70 ℃ and pH of 2-13:applications to habitability and nitrogen cycling in low-temperature hydrothermal systems[J].Geochimica et Cosmochimica Acta,2012,84:280-296

    • [34] Deng Y Y,Li Y Z,Li L.Experimental investigation of nitrogen isotopic effects associated with ammonia degassing at 0-70 ℃[J].Geochimica et Cosmochimica Acta,2018,226:182-191

    • [35] Cejudo E,Schiff S L.Nitrogen isotope fractionation factors(α)measured and estimated from the volatilisation of ammonia from water at pH 9.2 and pH 8.5[J].Isotopes in Environmental and Health Studies,2018,54(6):642-655

    • [36] Felix J D,Elliott E M,Gish T,et al.Examining the transport of ammonia emissions across landscapes using nitrogen isotope ratios[J].Atmospheric Environment,2014,95:563-570

    • [37] Ti C P,Ma S T,Peng L Y,et al.Changes of δ15N values during the volatilization process after applying urea on soil[J].Environmental Pollution,2021,270:116204

    • [38] Urey H C.The thermodynamic properties of isotopic substances[J].Journal of the Chemical Society,1947:562-581

    • [39] Walters W W,Chai J J,Hastings M G.Theoretical phase resolved ammonia-ammonium nitrogen equilibrium isotope exchange fractionations:applications for tracking atmospheric ammonia gas-to-particle conversion[J].ACS Earth and Space Chemistry,2019,3(1):79-89

    • [40] Kirshenbaum I,Smith J S,Crowell T,et al.Separation of the nitrogen isotopes by the exchange reaction between ammonia and solutions of ammonium nitrate[J].The Journal of Chemical Physics,1947,15(7):440-446

    • [41] Pan Y P,Tian S L,Liu D W,et al.Fossil fuel combustion-related emissions dominate atmospheric ammonia sources during severe haze episodes:evidence from 15N-stable isotope in size-resolved aerosol ammonium[J].Environmental Science & Technology,2016,50(15):8049-8056

    • [42] Moore H.The isotopic composition of ammonia,nitrogen dioxide and nitrate in the atmosphere[J].Atmospheric Environment,1977,11(12):1239-1243

    • [43] Heaton T H E.15N/14N ratios of nitrate and ammonium in rain at Pretoria,South Africa[J].Atmospheric Environment,1987,21(4):843-852

    • [44] Savard M M,Cole A,Smirnoff A,et al.δ15N values of atmospheric N species simultaneously collected using sector-based samplers distant from sources-isotopic inheritance and fractionation[J].Atmospheric Environment,2017,162:11-22

    • [45] Li L,He Y Y,Zhang Z,et al.Nitrogen isotope fractionations among gaseous and aqueous NH+4,NH3,N2,and metal-ammine complexes:theoretical calculations and applications[J].Geochimica et Cosmochimica Acta,2021,295:80-97

    • [46] Zhang Z Y,Zeng Y,Zheng N J,et al.Fossil fuel-related emissions were the major source of NH3 pollution in urban cities of northern China in the autumn of 2017[J].Environmental Pollution,2020,256:113428

    • [47] Lin C T,Jickells T D,Baker A R,et al.Aerosol isotopic ammonium signatures over the remote Atlantic Ocean[J].Atmospheric Environment,2016,133:165-169

    • [48] Heaton T H E,Spiro B,Robertson S M C.Potential canopy influences on the isotopic composition of nitrogen and sulphur in atmospheric deposition[J].Oecologia,1997,109(4):600-607

    • [49] Liu X Y,Xiao H W,Xiao H Y,et al.Stable isotope analyses of precipitation nitrogen sources in Guiyang,southwestern China[J].Environmental Pollution,2017,230:486-494

    • [50] Chen F J,Lao Q B,Li Z Y,et al.Monthly variations of the nitrogen isotope of ammonium in wet deposition in a tropical city of south China[J].Aerosol and Air Quality Research,2020,20(5):1062-1069

    • [51] Bhattarai N,Wang S X,Xu Q C,et al.Sources of gaseous NH3 in urban Beijing from parallel sampling of NH3 and NH+4,their nitrogen isotope measurement and modeling[J].Science of the Total Environment,2020,747:141361

    • [52] Berner A H,Felix J D.Investigating ammonia emissions in a coastal urban airshed using stable isotope techniques[J].Science of the Total Environment,2020,707:134952

    • [53] Chang Y H,Zou Z,Zhang Y L,et al.Assessing contributions of agricultural and nonagricultural emissions to atmospheric ammonia in a Chinese megacity[J].Environmental Science & Technology,2019,53(4):1822-1833

  • 基本信息

    中图分类号: X513
    文献标识码: A
    DOI: 10.13878/j.cnki.jnuist.20220216001

    基金信息

    国家自然科学基金(41073019)；

    引用信息

    稿件历史

    收稿日期: 2022-02-16

  • 参考文献

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    • [29] Huang S N,Elliott E M,Felix J D,et al.Seasonal pattern of ammonium 15N natural abundance in precipitation at a rural forested site and implications for NH3 source partitioning[J].Environmental Pollution,2019,247:541-549

    • [30] Shao S C,Zhang Y L,Chang Y H,et al.Online characterization of a large but overlooked human excreta source of ammonia in China's urban atmosphere[J].Atmospheric Environment,2020,230:117459

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    • [33] Li L,Lollar B S,Li H,et al.Ammonium stability and nitrogen isotope fractionations for NH+4-NH3(aq)-NH3(gas)systems at 20-70 ℃ and pH of 2-13:applications to habitability and nitrogen cycling in low-temperature hydrothermal systems[J].Geochimica et Cosmochimica Acta,2012,84:280-296

    • [34] Deng Y Y,Li Y Z,Li L.Experimental investigation of nitrogen isotopic effects associated with ammonia degassing at 0-70 ℃[J].Geochimica et Cosmochimica Acta,2018,226:182-191

    • [35] Cejudo E,Schiff S L.Nitrogen isotope fractionation factors(α)measured and estimated from the volatilisation of ammonia from water at pH 9.2 and pH 8.5[J].Isotopes in Environmental and Health Studies,2018,54(6):642-655

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    • [52] Berner A H,Felix J D.Investigating ammonia emissions in a coastal urban airshed using stable isotope techniques[J].Science of the Total Environment,2020,707:134952

    • [53] Chang Y H,Zou Z,Zhang Y L,et al.Assessing contributions of agricultural and nonagricultural emissions to atmospheric ammonia in a Chinese megacity[J].Environmental Science & Technology,2019,53(4):1822-1833

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