Abstract.A PM 1 (i.e. particulate matter with an aerodynamic diameter less than 1.0 µm) short-term monitoring campaign was carried out in the Agri Valley (southern Italy) in September 2012. This area is of international concern, since it houses one of the largest European on-shore reservoirs and the largest oil/gas pre-treatment plant (i.e. the Centro Olio Val d'Agri -COVA) within an anthropised context. PM 1 measurements were performed in Viggiano, the nearest town to the COVA plant and one of the most populated towns of the Agri Valley. During the study period, the PM 1 daily concentrations ranged from 1.2 to 8.4 µg m −3 , with a mean value of 4.6 µg m −3 . Regarding the PM 1 chemical composition, it can be observed that S and typical crustal elements were the most abundant constituents of the PM 1 collected. By applying principal component analysis (PCA), it was pointed out that crustal soil, biomass and wood burning, secondary atmospheric reactions involving COVA plant emissions and local soil particles, and traffic were the main sources contributing to the PM 1 measured in the area under study. Moreover, a possible contribution of the long-range transport of African dust was observed.