The size distribution and composition of the atmospheric aerosol at a rural and nearby urban location

Abstract At a suburban location near Vienna and in the center of Vienna the aerosol was sampled with a 10 stage rotating cascade impactor permitting the classification of the aerosol particle sizes between aerodynamic diameters of 15 nm and 16 um. Both sampling sites were at an elevated location. Gravimetric, light absorption and PIXE analysis have been performed for all samples. The light absorption analysis also gives the concentration of black carbon, the PIXE analysis yielded concentrations of Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, and Pb. The mass size distribution of the aerosol for most of the elements had two modes. One peak occurred between 0.2 and 0.8 um, the coarse particles had a slight peak usually above 3 μm. On occasions an indication of a third peak below 50 nm could be observed. The total mass of the submicrometer particles was more than half of the total mass, except for calcium and iron. Little difference between the mass of the submicrometer particles at the two locations was found, except for Ca, Pb, and black carbon. The particles were generally larger at the suburban location. The light absorbing particles mostly had only one peak at a diameter of 0.2 um, thus being smaller than the other particles. Soot at the suburban location was a factor of 2 less and slightly larger than at the urban site. The similarity of the size distribution for almost all elements between the urban and the suburban location, as well as similarities to the arctic haze and the aerosol in Northern Europe suggests that the aerosol predominately originates from non-local sources and might be considered the central and north European average aerosol. Differences to aerosol characteristics at other locations exist. On a day-to-day basis the aerosol shows a very high variability.