Source apportionment and diurnal dynamics from quasi real-time measurements of potentially toxic elements in PM10 in a coastal industrial zone

This study provides a comprehensive characterization of potentially toxic elements (PTEs) in PM10 and associated pollutants in a heavily industrialized coastal area in central Chile. To investigate diurnal variability, the influence of wind regimes, particle-size relationships, and emission sources, hourly quasi real-time measurements of elemental concentrations, size-resolved particle data, black carbon (BC) source apportionment, and receptor modeling were integrated. The land–sea breeze cycle strongly modulated pollutant dispersion. Afternoon onshore winds promoted dilution, resulting in minimum concentrations. Meanwhile, nocturnal flows and northeasterly winds transported emissions from industrial facilities toward the monitoring site. Size-segregated analysis distinguished soil resuspension from fine particles enriched in metals derived from combustion. Mn was correlated across all size fractions, while Cu, Zn, and As dominated the fine mode, and Cr, Ni, and V dominated the intermediate fraction. Coarse particles prevailed during the day due to resuspension, while the fine and intermediate fractions increased at night under stable conditions. PCA and PMF resolved five source factors: Marine Aerosol (37%), Soil Dust (20%), Coal Combustion (13%), and two industrial factors (4% each). WRF simulations further showed that nocturnal recirculation, northeasterly transport, and coastal barrier effects can interact with boundary layer stability to produce short-term concentrations of PTEs. These findings highlight the importance of identifying meteorological typologies that drive acute pollution events in coastal industrial regions. By explicitly resolving diurnal dynamics and source contributions, this study addresses critical knowledge gaps in South America's coastal industrial zones and provides a foundation for targeted air quality management strategies.