The objective of this study is to compare the PM2.5 chemical composition and sources at a rural background site in Central Europe between the years 1993/1994/1995 and 2009/2010. Chemical analysis of PM2.5 for 29/26 elements by PIXE and water-soluble inorganic ions by IC (2009/2010) was performed. The Positive Matrix Factorization (PMF) was applied to the chemical composition of PM2.5 to identify its sources. The results of chemical analysis and source apportionment have been compared. The decrease in time of almost all elements concentrations especially the metals regulated by the EU Directive are evident. The median ratios show significant improvement in levels of analysed elements in PM2.5. Slight increase of K levels points to rise in the residential wood combustion. The apportioned sources in the years 1993/94/95 were brown coal combustion, oil combustion, dust – long-range transport, re-suspended dust/soil and black coal combustion. The industrial combustion of brown/black coal and oil of the regional origin dominated. The six factors in the years 2009/2010 were assigned as sulphate, nitrate, residential heating, industry, re-suspended dust, sea salt + dust/soil – LRT. The secondary sulphate from coal combustion and residential biomass burning of the local origin dominated.