Aerosol samples were collected using Berner-type cascade impactor and stacked filter units at Siófok during four campaigns in 1999 and 2000. A total of 40 bulk samples were measured using X-ray fluorescence (XRF). The concentrations of light elements in individual particles were calculated using a reverse Monte Carlo method developed at the University of Antwerp. The particles were further classified using hierarchical and non-hierarchical cluster analyses. Around 25,000 individual particles were analyzed by computer-controlled electron probe microanalysis (EPMA). In order to determine the possible sources of the aerosol particles, the combined data set of the bulk XRF and single-particle EPMA results was subjected to principal component analysis. The obtained analytical results were compared to the air mass backward trajectories, showing good correlation for the sampling periods. The composition of the aerosol did not show characteristic seasonal variation, it was more correlated to the origin of the incoming air mass.