Chemical composition and oxidative potential of atmospheric coarse particles at an industrial and urban background site in the alpine region of northern Italy

Abstract

The chemical composition and oxidative potential (OP) of particulate matter (PM10) samples were investigated at an industrial (Ala) and a background (TN) site in northern Italy. Three emission sources of airborne metals were identified by Positive Matrix Factorization (PMF) analysis, i.e., the zinc coating facility located in the area, the traffic on the nearby motorway and the pesticides normally used in the extensive vineyard cultivation. PM10 redox activity was measured using dithiothreitol (OPDTTV) and ascorbic acid (OPAAV) cell-free assays. Similar OPDTTV responses were obtained at the two sites (0.60 ± 0.23 mmol min−1 m−3), while higher (OPAAV) values were measured at Ala (1.4 ± 1.1 nmol min−1 m−3) than at TN (0.7 ± 0.4 nmol min−1 m−3). Overall, both OPDTTV and OPAAV responses were found to be broadly correlated with several inorganic species, namely ions and soluble metals, and organic components. In particular, OPAAV responses are mainly affected by Zn directly emitted from the zinc factory and Cu used in the vineyard cultivation. Therefore, the higher OPAAV values measured at Ala can be explained by the higher concentration of these metals at the industrial site.