Particle emissions generated during different stages of pyrolysis/incineration of refused derived fuel at the outlet of a pilot scale incinerator were characterized for mobility (with SNIPS), total mass concentration (by filters) as well as by an optical particle counter and an impactor. Samples were extracted at a gas temperature 600degreesC and cooled to about 150degreesC. Total mass reached its peak of about 30 mg/Nm(3) during pyrolysis following the addition of fresh fuel, and dropped to a minimum around 2 mg/Nm(3) during after-combustion, as would be expected. Emissions during all stages were exclusively in the submicron range with number concentrations of 10(5)-10(6) cm(-3) and median diameters between 0.05 and 0.15 muM. The upper ends of those ranges were attained during the transition from pyrolysis to combustion. No particles above 1 mum were detected with any of the instruments. (C) 2003 Elsevier Ltd. All rights reserved.