Tropospheric aerosols (total suspended particulate, TSP) were sampled at four sampling sites of various anthropogenic impact (industrial, commercial, heavy trafficked, and mixed urban influence), located in Dar es Salaam, the commercial capital of Tanzania. Air concentrations of minor and trace elements (Al, As, Br, Ca, Cd, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Si, Sb, and Zn) in TSP were determined by means of wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry and inductively coupled plasma atomic emission spectrometry (ICP-AES). From these data, the main ionic composition of particulate matter was inferred by means of a species correlation/ratio-derived approach, based on former studies of the region. Enrichment factors, bivariate correlations, diagnostic ratios, and chemical mass closures were calculated utilizing the concentration data of TSP constituents for each site in order to reveal the emission sources. A couple of diagnostic ratios (Ni/Cd, Zn/Cd, Br/Ni, Ni/Sb) were useful for source identification, e.g., motor vehicle exhaust and non-exhaust emissions. Significant increases in concentrations of As, Br, Cr, Cu, Mn, Ni, Pb, and Zn were observed, as compared to results for the city before 2010. Moreover, first-time air levels are reported for Cd and Sb, which are important markers of non-exhaust emissions. Air quality indices and calculations with the AIRQ + model have foreseen increases in the negative health effects of the sensitive groups of the local population at the study areas, especially those with heavy traffic, industrial, and/or mixed urban influence.

中文翻译：

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坦桑尼亚达累斯萨拉姆四个采样点大气气溶胶中微量元素和微量元素的日间浓度

对流层气溶胶（总悬浮颗粒物，TSP）在位于坦桑尼亚商业首都达累斯萨拉姆的四个各种人为影响（工业、商业、交通繁忙和混合城市影响）的采样点进行采样。TSP 中微量元素和微量元素（Al、As、Br、Ca、Cd、Cl、Cr、Cu、Fe、K、Mg、Mn、Na、Ni、Pb、S、Si、Sb 和 Zn）的空气浓度为通过波长色散 X 射线荧光 (WDXRF) 光谱法和电感耦合等离子体原子发射光谱法 (ICP-AES) 测定。从这些数据中，基于对该地区的先前研究，通过物种相关性/比率衍生方法推断了颗粒物的主要离子组成。富集因子、双变量相关性、诊断比率、利用每个站点的 TSP 成分的浓度数据计算化学质量关闭，以揭示排放源。一些诊断比率（Ni/Cd、Zn/Cd、Br/Ni、Ni/Sb）可用于源识别，例如机动车尾气和非尾气排放。与 2010 年之前的城市结果相比，观察到 As、Br、Cr、Cu、Mn、Ni、Pb 和 Zn 的浓度显着增加。此外，首次报告了 Cd 和 Sb 的空气含量，它们是非废气排放的重要标志。空气质量指数和使用 AIRQ + 模型的计算已经预见到研究区域当地人口敏感群体的负面健康影响会增加，尤其是那些交通繁忙、工业和/或混合城市影响的人群。