Characterization of PM_2.5 and its oxidative potential in three regions of Southern Italy

Introduction: The study of the atmospheric particulate matter (PM) oxidative potential (OP), a general indicator of human health risks associated with PM exposure, has become a focal point in research. However, in the Italian territory, the number of studies concerning OP is limited, especially for the fine fraction of particulate matter (PM_2.5). This study aims at investigating the impact of different natural and anthropogenic sources on PM_2.5 and its oxidative potential in different areas of Southern Italy.

Methods: Samples of PM_2.5 were collected in sites of different typology (i.e. rural, urban background, urban and industrial sites) from three regions of Southern Italy. The PM_2.5 sources were identified and characterized with the PMF5.0 receptor model, while the contribution of each source to the OP (measured with a DTT assay) was estimated with the MLR approach. The results were compared with those obtained from other similar studies performed in Northern Italy, related to different typology sites.

Results and conclusions: The PMF5.0 identified similar sources for the southern sites (biomass combustion, vehicular traffic, crustal and marine contributions, secondary inorganic aerosols and industrial emissions), with different contributions to PM_2.5 and OP. The MLR analysis highlighted that combustion sources (i.e., biomass combustion and traffic emissions) were the main contributors to the OP activity of PM_2.5. Furthermore, it was also observed that the relative contributions to OP and PM_2.5 were not comparable for all sources. The results of this study represent a contribution to a better understanding of the potential health impact of PM_2.5; of its spatial variability; and of the role of different sources.