Aerosol samples have been collected in urban air by means of Nuclepore polycarbonate membrane filters from October 29, 1991 to October 17, 1994. Parallel sampling has been made from September 15, 1993 to October 17, 1994 with a stacked filter unit, too. The elemental composition of the samples was determined by PIXE. Yearly, winter and summer averages of elemental concentrations have been calculated together with enrichment factors. Principal components analysis has derived four factors, elemental source profiles and contributions of various sources.