RESUMEN
The aim of this study was to assess PM10 pollution level and estimate required source emission reduction in Belgrade area, the second largest urban center in the Balkans. Daily mass concentrations and trace metal content (As, Cd, Cr, Mn, Ni, Pb) of PM10 were evaluated for three air quality monitoring sites of different types: urban-traffic (Slavija), suburban (Lazarevac) and rural (Grabovac) under the industrial influence, during the period of 2012-13. Noncompliance with current Air Quality Standards (AQS) was noticeable: annual means were higher than AQS at Slavija and Lazarevac, and daily frequency threshold was exceeded at all three locations. Annual means of As at Lazarevac were about four times higher than the target concentration, which could be attributed to the proximity of coal-fired power plants, and dust resuspension from coal basin and nearby ash landfills. Additionally, levels of Ni and Cr were significantly higher than in other European cities. Carcinogenic health risk of inhabitants' exposure to trace metals was assessed as well. Cumulative cancer risk exceeded the upper limit of acceptable US EPA range at two sites, with Cr and As as the major contributors. To estimate source emission reduction, required to meet AQS, lognormal, Weibull and Pearson 5 probability distribution, functions (PDF) were used to fit daily PM10 concentrations. Based on the rollback equation and best fitting PDF, estimated reduction was within the range of 28-98%. Finally, the required reduction obtained using two-parameter exponential distribution suggested that risks associated to accidental releases of pollutants should be of greater concern.