CHARACTERIZATION OF DUSTY AND DUST FREE PM SAMPLES COLLECTED IN A SUBURBAN SITE IN SOUTHERN ITALY

PM10 and PM2.5 samples simultaneously collected at a suburban site of south eastern Italy have been analysed with the main aim of determining the atmospheric dust contribution and investigating the dust source impact. Low volume samplers were used to collect 24-h PM10 and PM2.5. Organic and elemental carbon, inorganic ions, and selected metals were measured in the collected samples. EC and OC were determined by thermal optical transmittance technique (Sunset Carbon Analyzer), soluble ions (SO42-, NO3-, NH4+, Cl-, Na+, K+, Mg2+ and Ca2+) were analysed via High Performance Ion Chromatography (HPIC, Dionex DX-500 System); eight trace elements (Ni, Cu, V, Mn, As, Pb, Cr, Sb) were analyzed via Graphite Furnace Atomic Absorption Spectroscopy (GF-AAS, Perkin Elmer Analyst 600 System); four trace elements (Fe, Al, Zn and Ti) were analysed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES, Varian Liberty 110 spectrometer). Moreover, ATR-FTIR analysis were performed on samples of Saharan Dust event and samples characterized by mass air transported from NE Europe. ATR-FTIR analysis let identify organic functional groups including non-acid organic hydroxyl C-OH group (eg sugars, anhydrosugars, and polyols) and carbonyl C=O group, carboxylic acid COOH group, aromatic and aliphatic unsaturated C=C-H group, aliphatic saturated C-C-H group, and amine NH2 group. Some inorganic ions have also been identified: carbonates, sulfate, silicate and ammonium. In this work, the X-ray photoelectron spectroscopy (XPS) has been used to investigate surface chemical composition of particulate matter. The mass closure analysis have been applied to the chemically speciated PM10 and PM2.5 samples to identify main natural and anthropogenic sources and determine the atmospheric dust contribution. Analytical back trajectories combined with statistical analyses and satellite true colour images were used to know about the location of potential source regions and to determine the contribution of long range transported air masses. In particular the effect of Sahara dust outbreak on PM composition was evaluated.