The results of a study of the elemental concentrations in PM₁₀ samples collected at a site in southwest Mexico City during 2016 and 2019, are presented. The concentrations of up to 19 elements were measured with X-ray fluorescence (XRF). These analyses were complemented with ion chromatography for eight ionic species (for the samples collected in 2016). The behaviors of the gravimetric mass and elemental concentrations are described for the morning, afternoon, and night-time periods in 2019. The elemental concentrations observed in the PM₁₀ samples did not present significant changes as compared to those published in previous works. It was found that the gravimetric mass concentrations were always below the official standards, except during a contingency period in May 2019. The positive matrix factorization (PMF) receptor model was used to identify contaminating sources and their relative contributions to the concentrations of the detected elements. The soil-related factors were the most abundant contributors, with other components associated to traffic, biomass burning, fuel oil, secondary aerosol, and dust resuspension. The occurrence of episodes in 2019 is explained with the aid of PMF and back-trajectories, while the contingency period is due to other chemical species not detected in PM₁₀ with XRF. A comparison with data collected in 2005 in downtown Mexico City is also carried out, as well as with urban areas in other countries.

介绍了 2016 年和 2019 年在墨西哥城西南部某个地点收集的PM ₁₀样品中元素浓度的研究结果。使用 X 射线荧光 (XRF) 测量多达 19 种元素的浓度。这些分析还通过离子色谱法对八种离子物质进行了补充（对于 2016 年收集的样品）。描述了 2019 年上午、下午和夜间时段的重量质量和元素浓度的行为。在 PM ₁₀样品中观察到的元素浓度与以前的作品中发表的相比没有出现显着变化。结果发现，除了2019年5月的应急期间外，重量质量浓度始终低于官方标准。采用正矩阵分解（PMF）受体模型来识别污染源及其对检测元素浓度的相对贡献。与土壤相关的因素是最丰富的因素，其他因素与交通、生物质燃烧、燃油、二次气溶胶和灰尘再悬浮有关。 2019 年事件的发生可以借助 PMF 和反向轨迹来解释，而应急期则是由于XRF未在 PM ₁₀中检测到的其他化学物质造成的。还与 2005 年在墨西哥城市中心以及其他国家的城市地区收集的数据进行了比较。