The seasonal and spatial variations of particulate matter (PM2.5–10 and PM2.5) and its chemical composition have been studied over a one-year period in Kenitra city (2007–2008). The samples were collected using Gent stacked filters and dichotomous samplers in two size fractions: below 2.5 μm (fine) and 2.5 to 10 μm (coarse). The chemical compositions of the collected filters were evaluated by using Total X-ray Fluorescence and Atomic Absorption Spectroscopy. The influence of atmospheric transport scenarios on the levels of PM was elaborated by means of air mass back-trajectories, using the HYSPLIT™ model. This study allowed identifying four main transport patterns: short local flows over the Kenitra region, Northwesterly flows over the Atlantic Ocean, Northerly flows, and Southern flows. The highest PM2.5–10 concentrations were observed in the summer and the lowest in the winter. However, no significant seasonal variations were discerned for PM2.5 particles. The enrichment factor and risk assessment code were calculated to distinguish between anthropogenic influences and the natural background levels and assess the environmental risks of metals in PM2.5–10 and PM2.5 particles. A comparison of PM and metal concentrations in Kenitra city and other African cities (reported in the literature) revealed that that the values obtained in Kenitra city are significantly higher than those recorded for the other African cities (that are the subject of the comparison).

中文翻译：

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摩洛哥凯尼特拉市大气中PM2.5和PM2.5-10的季节性变化和风险评估

在凯尼特拉市（2007-2008）进行了为期一年的研究，研究了颗粒物（PM2.5-10和PM2.5）及其化学成分的季节性和空间变化。使用Gent堆叠式过滤器和二分采样器以两个尺寸部分（小于2.5μm（精细）和2.5至10μm（粗））收集样品。通过使用总X射线荧光和原子吸收光谱法评估收集的过滤器的化学组成。使用HYSPLIT™模型，通过空气质量的反向轨迹，详细说明了大气运输情景对PM水平的影响。这项研究可以确定四种主要的运输方式：肯尼特拉地区的局部短流量，大西洋上空的西北风，北部风和南部风。最高的PM2。夏季观察到5-10的浓度，冬季观察到最低的浓度。但是，没有发现PM2.5颗粒有明显的季节性变化。计算了富集因子和风险评估代码，以区分人为影响和自然本底水平，并评估PM2.5-10和PM2.5颗粒中金属的环境风险。对Kenitra市和其他非洲城市的PM和金属浓度进行比较（文献报道）表明，Kenitra市获得的值显着高于其他非洲城市（比较的对象）所记录的值。计算了富集因子和风险评估代码，以区分人为影响和自然本底水平，并评估PM2.5-10和PM2.5颗粒中金属的环境风险。对Kenitra市和其他非洲城市的PM和金属浓度进行比较（文献报道）表明，Kenitra市获得的值显着高于其他非洲城市（比较的对象）所记录的值。计算了富集因子和风险评估代码，以区分人为影响和自然本底水平，并评估PM2.5-10和PM2.5颗粒中金属的环境风险。对Kenitra市和其他非洲城市的PM和金属浓度进行比较（文献报道）表明，Kenitra市获得的值显着高于其他非洲城市（比较的对象）所记录的值。