Sources and health risk of metallic elements assessment: a study of a representative industrial city

PM_2.5 in the air can adsorb a wide range of substances, and due to their small size, they can carry toxic and hazardous substances into the human body through inhalation, which can be harmful to human health. PM_2.5 samples were collected in Shihezi for one year from September 2021 to August 2022 to characterise the distribution of 13 metallic elements in PM_2.5 and their potential sources. The findings revealed that the concentrations of PM_2.5 surpassed the national threshold of 35 μg/m³, alongside elevated levels of crustal elements. To assess the potential sources of the 13 metallic elements, present in PM_2.5, a comprehensive analysis was conducted utilizing Enrichment Factor analysis, principal component analysis (PCA), and Backward Trajectory Modelling. The Enrichment Factors analysis revealed that five elements were significantly influenced by anthropogenic activities, with cadmium exhibiting particularly high levels of enrichment. PCA indicated that the metal elements were predominantly sourced from coal combustion, vehicular emissions, dust, fossil fuel combustion and industrial activities. Backward trajectory cluster analysis demonstrated that pollutant concentrations are substantially affected by both long-range transport mechanisms and localized anthropogenic sources. The assessment of health risks associated with metallic elements suggests a low risk to human health. These findings offer a crucial scientific foundation for air pollution management strategies in the SHZ region.