Source apportionment of PM10 in the Western Mediterranean based on observations from a cruise ship

Two intensive PM10 sampling campaigns were performed in the summers of 2009 and 2010 on the ship Costa Pacifica during cruises in the Western Mediterranean. Samples, mainly collected on a hourly basis, were analysed with different techniques (Particle Induced X-Ray Emission, PIXE; Energy Dispersive – X Ray Fluorescence, ED-XRF; Ion Chromatography, IC; Thermo-optical analysis) to retrieve the PM10 composition and its time pattern. The data were used for obtaining information about the sources of aerosol, with a focus on ship emissions, through apportionment using chemical marker compounds, correlation analysis and Positive Matrix Factorization (PMF) receptor modeling. For the campaign in 2010, 66% of the aerosol sulphate was found to be anthropogenic, only minor contributions of dust and sea salt sulphate were observed while the biogenic contribution, estimated based on the measurements of MSA, was found to be more important (26%), but influenced by large uncertainties. V and Ni were found to be suitable tracers of ship emissions during the campaigns. Four sources of aerosol were resolved by the PMF analysis; the source having the largest impact on PM10, BC and sulphate was identified as a mixed source, comprising emissions from ships. Ship emissions were observed to have a dominating impact on sulphate in aerosol for the leg Palma-Tunis, crossing a main ship route, and strong impacts also in some other parts of the route. However, looking at the entire dataset these impacts were much less pronounced and showed large spatial and temporal variations.JRC.H.2-Air and Climat