Impact of the New Sustainable Urban Mobility Plan on the Quality of Urban Dust: The Case of the City of Murcia (SE Spain)

In 2023, Murcia implemented a new sustainable urban Mobility Plan emphasizing pedestrianization, segregated public transportation, and the reduction of private vehicle traffic within the city. Consequently, this study aimed to evaluate heavy metal pollution in urban dust by comparing data collected prior to the plan’s implementation (2016) with that obtained afterward (2025). Systematic sampling of urban dust was conducted at 84 sites during both study periods. The concentrations of elements were quantified employing inductively coupled plasma mass spectrometry. The K-means algorithm was employed to identify data clusters. The analysis revealed a distinct geochemical shift, with the dominant elemental abundance changing from Fe > Zn > Mn > Pb > Cu > Cr in 2016 to Fe > Zn > Mn > Cu > Cr > Pb by 2025. Concentrations of Pb and Mn declined following the implementation of the Mobility Plan, whereas levels of As exhibited an increase between 2016 and 2025. Children are at risk of exposure arising from As, which was identified as the contaminant of greatest concern. The Murcia Mobility Plan, implemented in 2023, had a significant and multifaceted impact. It led to a decrease in traditional metal contaminants and simultaneously highlighted the emergence of new contaminants, such as arsenic (As).