Anthropogenic and biogenic tracers in fine aerosol based on seasonal distributions of dicarboxylic acids, sugars and related compounds at a rural background site in Central Europe
Anthropogenic and biogenic tracers in fine aerosol based on seasonal distributions of dicarboxylic acids, sugars and related compounds at a rural background site in Central Europe
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DOI：
10.1016/j.atmosenv.2023.119619
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发表时间：
2023-01
影响因子：
5
通讯作者：
P. Vodička;K. Kawamura;D. Deshmukh;P. Pokorná;J. Schwarz;V. Ždímal
中科院分区：
文献类型：
--
作者：
P. Vodička;K. Kawamura;D. Deshmukh;P. Pokorná;J. Schwarz;V. Ždímal
气溶胶中的水溶性有机化合物被认为是大气过程的相关指标。2013年9月27日至2014年8月9日，在代表中欧农村背景的国家大气观测站Košetice（NAOK）收集了细颗粒物（PM 1）样本。分析样品（n = 146）的水溶性二羧酸（以下简称为二酸）和相关化合物，以确定其季节性变化和来源。通过正矩阵因子分析（PMF），共识别出5个因子：2个人为因子、2个生源因子和1个背景因子，其中冬季人为因子对总有机质（OM）的贡献最大。与生物质燃烧（BB）有关的主要冬季人为因素1的典型示踪剂是脱水糖以及马来酸（M）、甲基马来酸（mM）和甲基琥珀酸（iC 5）。冬季BB因子占OM的64.1 ± 14.3%（年平均）。36.7± 27.4%）。一个次要的人为因素2的特点是邻苯二甲酸（Ph），对苯二甲酸（tPh）和酮丙二酸（KC 3），我们分配到二次燃烧产物。人为因素2的贡献全年处于相似水平（OM为12.5 ± 10.1%）。主要在冬季，虽然也在春季和秋季，是二次水相反应的特征形成的二酸，通常伴随着较低的温度，全球辐射和臭氧（O3）浓度，但较高的相对湿度（RH）和气溶胶液态水含量（ALWC）。生物源的二次有机气溶胶（SOA）典型代表为丙二酸（C3）、甲基丙二酸（iC 4）、3-氧代丙酸（ωC3）、4-酮庚二酸（kC 7）、7-氧代庚酸（ωC7）、庚二酸（C7）和辛二酸（C8）。其中，生物源1因子在夏季占主导地位，对有机质的贡献率为40.3 ± 19.6%，其它季节均低于10%。该因子主要表现为kC 7和ω C7酸浓度在夏季相对增加。第二个生源因子2在夏季也很显著（36.8 ± 20.5%），在春季占优势（34.9 ± 19.9%），由初级糖（果糖、半乳糖和蔗糖）、正链二酸（草酸（C2）至壬二酸（C9））及其氧化前体（ωC3、4-氧代丁酸（ωC4）和5-氧代戊酸（ωC5））代表。气相中SOA的光化学形成主要是夏季的特征，伴随着较高的温度、全球辐射和O3浓度以及较低的RH。此外，背景因素也得到了解决，它代表了没有明显季节变化的化合物，因此可以是人为的和生物的来源，并且主要含有较少的氧化化合物（甲基乙二醛（MeGly）、乙二醛（Gly）、乙醛酸（ωC2）和丙酮酸（Pyr））。
Water-soluble organic compounds in aerosols are considered as relevant indicators of atmospheric processes. Fine particulate matter (PM1) samples were collected at National Atmospheric Observatory Košetice (NAOK), a rural background site representative of Central Europe, from September 27, 2013 to August 9, 2014. The samples (n = 146) were analyzed for water-soluble dicarboxylic acids (hereafter referred to as diacids) and related compounds to identify their seasonal variations and origins. Based on the Positive Matrix Factorization (PMF) analysis, we identified 5 factors – 2 anthropogenic, 2 biogenic and 1 background factors.In winter, anthropogenic contributions dominated in total organic matter (OM). Typical tracers for the main winter anthropogenic factor 1, connected with biomass burning (BB), were anhydrosugars together with maleic (M), methylmaleic (mM) and methylsuccinic (iC5) acids. This BB factor accounted for 64.1 ± 14.3% of OM in winter (annual avg. 36.7 ± 27.4%). A secondary anthropogenic factor 2 was characterized by phthalic (Ph), terephthalic (tPh) and ketomalonic (kC3) acids, which we assigned to secondary combustion products. The contribution of anthropogenic factor 2 was at a similar level throughout the year (12.5 ± 10.1% in OM). Mainly in winter, although also in spring and autumn, was the characteristic formation of diacids by secondary aqueous phase reactions, typically accompanied by lower temperatures, global radiation and ozone (O3) concentrations, yet higher relative humidity (RH) and aerosol liquid water content (ALWC).In summer, contributions of biogenic origin dominated. Secondary organic aerosols (SOA) of biogenic origin were typically represented by malonic (C3), methylmalonic (iC4), 3-oxopropanoic (ωC3), 4-ketopimelic (kC7), 7-oxoheptanoic (ωC7), pimelic (C7) and suberic (C8) acids. The factor, named as Biogenic 1, was dominant in summer with a contribution of 40.3 ± 19.6% in OM, while in other seasons, its contribution was below 10%. This factor was mainly characterized by a relative summer increase in the concentrations of kC7and ωC7acids. The second biogenic factor 2, also significant in summer (36.8 ± 20.5%) and dominant in spring (34.9 ± 19.9%), was represented by primary sugars (fructose, galactose and sucrose), normal chain diacids (oxalic (C2) to azelaic (C9)) and their oxidative precursors (ωC3, 4-oxobutanoic (ωC4) and 5-oxopentanoic (ωC5) acids). The photochemical formation of SOA in the gas phase was characteristic mostly for the summer season, accompanied by higher temperatures, global radiation and O3concentrations, and lower RH.Additionally, background factor was resolved, which represents compounds with no distinctive seasonal variation and can therefore be of both anthropogenic and biogenic origin and contained mainly less oxidized compounds (methylglyoxal (MeGly), glyoxal (Gly), glyoxylic acid (ωC2) and pyruvic acid (Pyr)).