A kind of porous alumina was employed as bed material of bubbling fluidized bed coal combustion instead of non-porous silica sand. The effect of the bed material on emissions of N2O and NOx was evaluated using a bench-scale combustor. The present porous alumina suppressed N2O emission. This result is explained by the catalytic activity of porous alumina to decompose N2O. In addition, NOx emission with porous bed material was nearly the same as or lower than that for the sand bed. Thus the decrease in N2O without increasing NOx was attained.A modification of desulfurization by limestone was proposed. Fine limestone particles were employed as sorbent in order to conduct SO2 capture in the freeboard. By employing fine particles, the contact between volatile matter and limestone, which is known to increase the emission of NOx, was avoided. Thus the increase in NOx emission during limestone feed was avoided.