Chemical footprints of harmattan dust and traffic corridor particulates monitored at two environmentally distinct geopolitical zones in Nigeria
Chemical footprints of harmattan dust and traffic corridor particulates monitored at two environmentally distinct geopolitical zones in Nigeria
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DOI：
10.1007/s11356-020-10004-x
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发表时间：
2020-07-09
影响因子：
5.8
通讯作者：
Latif, Moufthou B.
中科院分区：
文献类型：
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作者：
Abiye, Olawale E.;Matthew, Olaniran J.;Latif, Moufthou B.
哈麦丹粉尘和与交通有关的污染一直是西非次区域严重的环境问题。为了进一步促进对该地区大气污染和化学成分的环境水平的了解，本研究监测了尼日利亚西南部（Ile-Ife）和西北部（扎里亚）地缘政治区四个地点的哈麦丹粉尘和交通相关颗粒物。使用配备优化的次级靶X射线激发条件（Al、CaF 2、Fe、Ge、Zr、Mo、Ag、Al 2 O3）的能量色散X射线荧光光谱仪表征所收集的样品的化学组成。目标是评估所有地点的时空质量浓度、化学足迹、富集系数、元素相关性和比率。用NIST SRM 2783空气颗粒物标准验证了X射线分析方法，并确定了每种化学物质的检测限。验证结果表明，标准物质的重现性良好，各元素的相对标准偏差比相应的标准值低1-13%。在北部，质量浓度达到2200亩/克，在南部达到1500亩/克。地壳标志元素的平均浓度范围为Al（5-27 μ gm（-3））、Si（5-856 μ gm（-3））、Ca（0.78-13 μ gm（-3））和Fe（2-13 μ gm（-3）），在哈麦丹期，特别是在西南地区，这些元素的含量最丰富。铬、铜和铅的最高平均浓度值分别为380、810和420 ngm（-3），记录在交通走廊，也记录了最高的富集系数。黑碳和元素浓度分别占整个地点的1%至54%和9%至94%。大气流动的位置向后的轨迹显示两个主要来源，来自撒哈拉沙漠和几内亚湾的海洋流动的沙尘源。这项研究发现，化学足迹（铝，硅，钾，钙，钛，铁）的哈美他坦相关的灰尘更相关（r（2）之间的0.88和0.99）比那些归因于灰尘再悬浮在交通位置。
Harmattan dust and traffic-related pollution have been a serious environmental concern in the West African sub-region. In order to further contribute to the understanding of ambient levels of atmospheric pollution and chemical composition in the region, this study monitored harmattan dust and traffic-related particulate matter at four locations across southwestern (Ile-Ife) and north-western (Zaria) geo-political zones of Nigeria. The collected samples were characterized for their chemical composition using Energy-Dispersive X-Ray Fluorescence spectrometer equipped with an optimized secondary target x-ray excitation conditions (Al, CaF2, Fe, Ge, Zr, Mo, Ag, Al2O3). The objectives are to assess spatio-temporal mass concentrations, chemical footprints, enrichment factors, elemental correlations, and ratios at all locations. The X-ray analytical method was validated with a NIST SRM 2783 air particulate standard, and detection limits for each chemical specie were determined. Validation results showed good reproducibility of the certified reference material with relative standard deviations of the elements much lower by about 1-13% than the corresponding reference values. Mass concentrations reached up to 2200 mu gm(-3)in the north and 1500 mu gm(-3)in the south. The range of mean concentration of crustal marker elements were Al (5-27 mu gm(-3)), Si (5-856 mu gm(-3)), Ca (0.78-13 mu gm(-3)), and Fe (2-13 mu gm(-3)), and were most abundant during the harmattan particularly in the southwestern region. Highest mean concentration values of 380, 810, and 420 ngm(-3)were recorded for Cr, Cu, and Pb respectively at the traffic corridor which also recorded the highest enrichment factors. Black carbon and elemental concentrations contributed between 1 to 54% and 9 to 94% across the locations respectively. Backward trajectories of atmospheric flow over the locations showed two dominant sources; dust laden source from the Sahara desert and maritime flow over the Gulf of Guinea. This study found that chemical footprints (Al, Si, K, Ca, Ti, and Fe) of harmattan-related dust were more correlated (r(2)between 0.88 and 0.99) than those attributed to dust re-suspension at the traffic location.