Significant atmospheric aerosols events over Buenos Aires, Argentina, during August 2003-March 2004 period were characterized in the present work. We analyzed solar UV radiation, aerosol optical depth and mineral composition, combining different sources of information: radiometric UV measurements, aerosol optical properties, microphysical derived data and aerosols collection. In particular, we study the attenuation produced by atmospheric aerosols on 380 nm narrowband solar radiation arriving at ground surface, during large contamination events occurred in Buenos Aires. For this study, we used the moderated narrow band radiometers GUV (Biospherical) of the Argentina Solar Monitoring Network. In particular we employed the instruments placed at CEILAP (Buenos Aires suburbs) and at INGEBI (Buenos Aires downtown). The intercomparison between these two instruments shows clearly the city pollution effect by the increase of solar attenuation in the second instrument, more influenced by traffic and other source emissions. A 2-stream radiative transfer model was used for deriving aerosol optical thickness for Buenos Aires at the study days. These results are compared with those determined from data taken by the CIMEL solar photometer (AERONET/NASA) placed at CEILAP. Also we made gravimetric measurements of fine (PM2.5), coarse (PM2.5-10) and total suspended particles (TSP), collected simultaneously during the extreme contamination events under study from samples taken outside the TANDAR/CNEA Laboratory, placed very near CEILAP. These aerosol samples were analysed using EDAX and PIXE techniques, in order to determine their elemental composition.