Through the use of fossil reserves and biomass to cover the ever increasing energy demand, there is a pollutant that must be analyzed in detail to know the effects and counteract. The air pollution has no discernible impact directly on the nature and creature. It takes a long time the load it is convened to harmful effects. The pollution is a result from the thermal utilization of biomasses and contains for example heavy metals, hydrogen sulfide and nitrogen oxides. The determination of ingredients and dust loadings of certain fuels is made by the pyrolysis and the use of a cascade impactor. The pyrolysis process is carried out in a thermogracimetric scale (TGA) under a nitrogen atmosphere. Then the pyrolysis gas is burned through an excess of oxygen to the nitrogen atmosphere on the Pt-catalyst of a differential scanning calorimeter (DSC). This combustion stream is then fed to the cascade impactor for analysis. The evaluation of fine particulate emission is done by analysis of the cut off fraction. The results of this work show that the installation of a cascade impactor has no impact on the measurement results of the TGA-DSC system. The measured results were compared with wood pellets and miscanthus pellets before and after the installation of the cascade impactor. After this series of experiments it is possible to analyze various fuels.