Transport Mechanisms and Pollutant Dynamics Influencing PM10 Levels in a Densely Urbanized and Industrialized Region near Naples, South Italy: A Residence Time Analysis

This study explores the transport mechanisms and pollutant dynamics influencing particulate matter concentrations at the Pomigliano d’Arco monitoring site, situated in a densely urbanized and industrialized region near Naples, Southern Italy, where daily PM10 averages consistently exceed EU thresholds. Exploiting an innovative residence time analysis, based on backward-trajectory analysis with the HYSPLIT model, we investigated air mass histories from 2018 to 2023 to identify predominant pollutant transport pathways and their temporal dynamics. Seven distinct airflow clusters were identified, with the most frequent originating from the western and northeastern directions, influenced by local circulation and long-range transport from the central Mediterranean and northern Africa. Seasonal variations revealed elevated PM10 levels during winter months, attributed to increased residential heating and temperature inversions, as well as summer peaks linked to Saharan dust transport and secondary aerosol formation. The residence time analysis highlighted regions within the central Mediterranean and northern Africa as significant contributors to high PM10 concentrations at the monitoring site, emphasizing the role of both local emissions and transboundary pollution. These findings provide critical insights for policymakers and air quality managers to develop targeted mitigation strategies aimed at reducing PM pollution in urban and industrialized areas, thereby enhancing public health and environmental sustainability.