Biomass is one of the most important renewable energy sources that could help to achieve the 2020 targets set by European Directive 2009/28. This is particularly true in Italy where the government plans to replace a final energy use corresponding to 200-250 PJ through the use of small wood stoves/boilers for domestic heating (<35 kW). This corresponds to about 25% of the national target for 2020. However, this solution is under discussion because of the environmental problems that poses in terms of emissions of PM and PAHs especially in lowland areas. The study, starting from these assumptions, was focussed to better characterize, with laboratory tests, the composition of PAHs emitted by a modern pellet stove and verify their distribution in the solid, liquid and gaseous fractions of the fumes at the stack. In brief, the tests showed that about 85% of the harmful effect of PAH is associated with the PM. This confirms that special attention should be given to the control of the dust through a better design of the stoves and/or the development of abatement equipment also suitable for small devices. (C) 2011 Elsevier Ltd. All rights reserved.