This study investigates the effects of fly ash compositions (SiO2 and Al2O3), particle sizes (4-10 mu m and 40 mu m), and concentrations on the simultaneous removals of fly ash and NO using a fluidized-bed catalyst reactor. Experimental results show that the removal efficiencies of fly ash and NO at particle concentrations of 968-11,181 mg m(-3) are 71-97% and 42-57%, respectively. SiO2 particles have more influences than Al2O3 particles on the performances of fluidized-bed CuO/AC catalyst. As the concentration of fine particle increases, the pores and active sites on catalyst surface are obstructed and therefore the activities of catalysts are depressed. (C) 2011 Elsevier B.V. All rights reserved.