Source apportionment of Particulate Matter in Campania (Italy): an integrated analytical and modelling approach.

Atmospheric particulate matter represents a complex environmental matrix whose concentration, chemical composition, and source contributions vary strongly across space and time, particularly in regions affected by the coexistence of urban, industrial, traffic, marine, and background influences. This PhD thesis investigates particulate matter in Campania, southern Italy, through an integrated analytical and modelling approach aimed at improving the characterization and source apportionment of PM in a complex Mediterranean environment. A field campaign was carried out in August 2024 across multiple monitoring sites representative of industrial, traffic-affected, port, school/urban, and rural background conditions. PM samples were characterized by gravimetric measurements, elemental analysis using Particle-Induced X-ray Emission, and single-particle investigation by Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy. These analytical data were integrated with receptor modelling by Positive Matrix Factorization and with trajectory-based tools, including HYSPLIT back-trajectories, Conditional Probability Function, and Potential Source Contribution Function analyses, to link chemical signatures with local wind sectors and regional transport pathways. The results highlighted pronounced spatial variability in PM mass and size fractions. Traffic-affected and industrial receptors showed the highest particulate loads, whereas the rural site provided a reference for the regional background. Elemental and single-particle evidence indicated a dominant crustal and resuspension component in the coarse fraction, a substantial secondary sulfate contribution in the fine fraction, and metal-enriched particles associated with traffic-related mechanical wear, industrial activities, and high-temperature combustion processes. At the Port of Naples, the enrichment of V and Ni provided a clear indication of shipping-related emissions. PMF resolved six main source categories: sea salt, mixed industrial/biomass-burning contributions, industry, waste incineration, secondary sulphates, and road dust. The coupling of PMF with CPF and PSCF allowed source contributions to be interpreted within both local and regional transport contexts. A complementary methodological component of the thesis focused on the development and validation of a Pb isotope analytical workflow by HR-MC-ICP-MS for future source-tracing applications in atmospheric PM. The evaluation of mass-bias correction models using NIST SRM 981 and Tl normalization showed that corrected Pb isotope ratios were compatible with reference values. Precision was mainly controlled by Pb concentration, with the 204Pb-based ratio representing the most critical case because of its low abundance and higher sensitivity to signal limitations and interference effects. Overall, this work demonstrates that combining elemental characterization, single-particle analysis, receptor modelling, transport analysis, and Pb isotope methodology provides a robust framework for disentangling local and regional PM sources in Campania. This integrated strategy can support more targeted air-quality monitoring and mitigation policies, while future work should focus on applying the optimized Pb isotope workflow to real atmospheric particulate samples.