Aerosol samples, divided into coarse and fine fractions, were collected on three Finnish EMEP stations during the spring and summer of 1991. Two of these stations are located on the Baltic Sea area, on the island of Uto about 80 km southwest from the coast of Finland and in Virolahti on the southeastern coast close to the Russian border. Ahtari is located in forested Central Finland. The samples were weighed and analysed by instrumental neutron activation analysis (INAA) for the elements chlorine, bromine, iodine, aluminium, manganese, sodium, titanium and vanadium. Meteorological parameters and the concentrations for ozone, ammonium, sulphur dioxide, nitrate, and sulphate are also obtained at these stations. Principal component analysis was performed on the data set. This allows the multi-dimensional data structure to be represented in two dimensions and the observation of groupings of objects and variables, sample dates and chemical and meteorological factors. Most of the variance was explained by the mass of the sample. The data analysis was especially useful in extracting the coarse aerosol fraction principal components. Marine, crustal, industrial and photochemical groupings were detected. The effect of the mainland could be observed in Uto. The formed groupings were supported by knowledge of chemical reactions and plots of the data. The effect of meteorological parameters, especially wind speed, humidity factors and temperature on the concentrations of different chemical components could be observed.