Department of Chemistry, Faculty of Science, University of Dhaka, Dhaka, 1000, Bangladesh.
Department of Chemistry, University of Iowa, Iowa City, IA, 52242, USA.
Environ Sci Pollut Res Int. 2018 Feb;25(5):4558-4569. doi: 10.1007/s11356-017-0695-6. Epub 2017 Nov 30.
This work focuses on the chemical characterization of fine aerosol particles (PM) collected from a rural remote island of the Bay of Bengal (Bhola, Bangladesh) from April to August, 2013. PM particle-loaded filters were analyzed for organic carbon (OC), elemental carbon (EC), water-soluble ions, and selected saccharides (levoglucosan, mannosan, galactosan, arabitol, and mannitol). The average PM mass was 15.0 ± 6.9 μg m. Organic carbon and elemental carbon comprised roughly half of the analyzed components. Organic carbon was the predominant contributor to total carbon (TC) and accounting for about 28% of PM mass. Secondary organic carbon (SOC) was inferred to be ~ 26% of OC. The sum of ions comprised ~ 27% of PM mass. The contribution of sea salt aerosol was smaller than expected for a sea-near site (17%), and very high chloride depletion was observed (78%). NssSO was a dominant ionic component with an average concentration of 2.0 μg m followed by Na, NH, and nssCa. The average concentration of arabitol and mannitol was 0.11 and 0.14 μg m, respectively, while levoglucosan and its stereoisomers (mannosan and galactosan) were bellow detection limit. NH/SO equivalent ratio was 0.30 ± 0.13 indicating that secondary inorganic aerosol is not the main source of SO. Enrichment factor (EF) analysis showed that SO and NO were enriched in atmospheric particles compared to sea aerosol and soil indicating their anthropogenic origin. Higher OC/EC ratio (3.70 ± 0.88) was a good indicator of the secondary organic compounds formation. Other ratios (OC/EC, K/EC, nssSO/EC) and correlation analysis suggested mixed sources for carbonaceous components. Arabitol and mannitol both showed strong correlation with EC having R value 0.89 and 0.95, respectively. Air mass trajectories analysis showed that concentrations of soil and anthropogenic species were lower for air masses originating from the sea (May-August) and were higher when air came from land (April).
本工作重点研究了 2013 年 4 月至 8 月从孟加拉湾（博尔纳）一个偏远农村岛屿采集的细颗粒气溶胶（PM）的化学特征。对载有 PM 颗粒的过滤器进行了有机碳（OC）、元素碳（EC）、水溶性离子和选定糖（左旋葡聚糖、甘露聚糖、半乳糖、阿拉伯糖醇和甘露醇）分析。PM 质量的平均值为 15.0 ± 6.9 μg m。有机碳和元素碳约占分析成分的一半。有机碳是总碳（TC）的主要贡献者，占 PM 质量的约 28%。推断出二次有机碳（SOC）约占 OC 的 26%。离子总和约占 PM 质量的 27%。海盐气溶胶的贡献小于近岸地区的预期（17%），且氯离子损耗非常严重（78%）。非海盐硫酸盐（NssSO）是主要的离子成分，平均浓度为 2.0 μg m，其次是 Na、NH 和非海盐钙。阿拉伯糖醇和甘露醇的平均浓度分别为 0.11 和 0.14 μg m，而左旋葡聚糖及其立体异构体（甘露聚糖和半乳糖）的浓度低于检测限。NH/SO 当量比为 0.30 ± 0.13，表明二次无机气溶胶不是 SO 的主要来源。富集因子（EF）分析表明，与海气溶胶和土壤相比，大气颗粒中的 SO 和 NO 更为富集，表明它们具有人为来源。较高的 OC/EC 比值（3.70 ± 0.88）是二次有机化合物形成的良好指标。其他比值（OC/EC、K/EC、非海盐硫酸盐/EC）和相关分析表明，碳质成分存在混合来源。阿拉伯糖醇和甘露醇与 EC 均具有很强的相关性，相关系数 R 值分别为 0.89 和 0.95。轨迹分析表明，起源于海洋的气团（5 月至 8 月）中土壤和人为物种的浓度较低，而起源于陆地的气团（4 月）中浓度较高。
