Characterization of PM10 sources in the Riotinto copper mining district (SW Spain) using multi-time-resolution receptor modelling

Mining activities significantly contribute to the emission of heavy metals and metalloids to the atmosphere. This year-long study (July 2024–July 2025) aimed to comprehensively characterize PM10 sources in the Riotinto copper mining district (southwestern Spain) using a highly time-resolved X-ray fluorescence monitor and an Aethalometer, and a high-volume sampler sampling daily on quartz fiber filters. Filters were chemically analyzed for multiple pollutants. High-time-resolution (1-h) and low-time-resolution (24-h) data subsets were integrated within a multi-time-resolution positive matrix factorization approach. The source apportionment analysis identified seven major PM10 sources: Waste Rock (4.9 µg·m-3), Regional + Traffic (3.6 µg·m-3), Dust (1.1 µg·m-3), Open Pit (1.6 µg·m-3), Aged Marine (1.2 µg·m-3), Copper Concentrate (0.7 µg·m-3), and Combustion (1.2 µg·m-3). The incorporation of species measured at daily resolution enabled the identification of traffic tracers and secondary organic aerosol in several factors, which was not possible using only the hourly-resolution data subset. During the study period, As represented the main geochemical anomaly because of its elevated concentration. This work highlights the advantages of combining data with different temporal resolutions in source apportionment analyses for a better characterization of emission sources in environmentally vulnerable areas.