Water-soluble dicarboxylic acids, oxoacids and α-dicarbonyls in the tropical aerosols in coastal megacity Mumbai: molecular characteristics and formation processes

IF 3 4区地球科学 Q2 ENVIRONMENTAL SCIENCES

Journal of Atmospheric Chemistry Pub Date : 2022-10-08 DOI:10.1007/s10874-022-09442-3

Ashmeet Kaur Alang, Shankar G. Aggarwal, Khem Singh, Daya Soni, Kimitaka Kawamura

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引用次数: 5

Abstract

Daytime and nighttime PM₁₀ samples were collected during summer (June) and winter (February) at a representative urban site in Mumbai, located on the western coast of Indian subcontinent. Samples were studied for molecular distribution of water-soluble dicarboxylic acids, oxoacids and dicarbonyls as well as total carbon (TC), water-soluble organic carbon (WSOC), inorganic ions along with specific markers (levoglucosan, K⁺) to better understand sources and formation processes of organic aerosols in Mumbai. The distribution of water-soluble organics was characterised by high abundance of oxalic acid (C₂), followed by phthalic (Ph), terephthalic (tPh), azelaic (C₉), malonic (C₃), and succinic acids (C₄). Positive correlations between C₂, sulfate and glyoxal (ωC₂) suggest secondary production of C₂ predominantly via aqueous phase chemistry. C₂ also showed positive correlation with K⁺ and levoglucosan indicating that biomass/biofuel burning is the potential source of diacids in the Mumbai aerosols. In addition, higher average contributions of total diacids to WSOC and OC in winter than in summer suggest that aerosols were aged i.e., photochemically well processed in winter in Mumbai. On the other hand, diurnal change in their ratios is observed with higher ratio in daytime samples than that of previous and succeeding nighttime samples, suggesting diacids are also influenced from local sources in both the seasons. This study demonstrates that biomass burning as well as biogenic sources are important sources influencing the distributions of aerosols in Mumbai.

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孟买沿海大城市热带气溶胶中的水溶性二羧酸、氧酸和α-二羰基:分子特征和形成过程

摘要在印度次大陆西海岸孟买某代表性城市站点采集夏季(6月)和冬季(2月)白天和夜间PM10样本。为了更好地了解孟买有机气溶胶的来源和形成过程，研究了样品中水溶性二羧酸、氧酸和二羰基的分子分布，以及总碳(TC)、水溶性有机碳(WSOC)、无机离子和特定标记物(左旋葡聚糖、K+)。水溶性有机物的分布以草酸(C2)丰度高为特征，其次为邻苯二甲酸(Ph)、对苯二甲酸(tPh)、壬二酸(C9)、丙二酸(C3)和琥珀酸(C4)。C2、硫酸盐和乙二醛之间的正相关(ωC2)表明C2主要通过水相化学进行二次生产。C2还与K+和左旋葡聚糖呈正相关，表明生物质/生物燃料燃烧是孟买气溶胶中二酸的潜在来源。此外，冬季总二酸对WSOC和OC的平均贡献高于夏季，表明孟买冬季气溶胶老化，即光化学处理良好。另一方面，观察到它们的比值的日变化，白天样品的比值高于之前和之后的夜间样品，这表明在两个季节中双酸也受到当地来源的影响。研究表明，生物质燃烧和生物源是影响孟买气溶胶分布的重要来源。

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来源期刊

Journal of Atmospheric Chemistry 地学-环境科学

CiteScore

4.60

自引率

5.00%

发文量

审稿时长

7.5 months

期刊介绍： The Journal of Atmospheric Chemistry is devoted to the study of the chemistry of the Earth''s atmosphere, the emphasis being laid on the region below about 100 km. The strongly interdisciplinary nature of atmospheric chemistry means that it embraces a great variety of sciences, but the journal concentrates on the following topics: Observational, interpretative and modelling studies of the composition of air and precipitation and the physiochemical processes in the Earth''s atmosphere, excluding air pollution problems of local importance only. The role of the atmosphere in biogeochemical cycles; the chemical interaction of the oceans, land surface and biosphere with the atmosphere. Laboratory studies of the mechanics in homogeneous and heterogeneous transformation processes in the atmosphere. Descriptions of major advances in instrumentation developed for the measurement of atmospheric composition and chemical properties.