The effects of iron and calcium compounds on NO emission during CZC (cabazole char) gasification under different O-2 concentrations have been investigated in a quartz tube fixed bed reactor. Temperature-programmed gasification was preformed to determine the influence of O-2 concentration and catalytic effects of iron and calcium on NO emission. The results show that the O-2 concentration strongly influences NO emission during CZC gasification; suitable O-2 Concentration could largely reduce NO emission, but high or low O-2 concentration is unfavorable to reduce NO pollution. Iron catalysts increase NO emission during CZC gasification in O-2 concentration ranging from 20.9 to 1.2%, and their catalytic effects are strongly depended on O-2 concentration. The order of their catalytic effects is Fe(AC)(2)> FeCl(2)approximate to FeCl3. Different kinds of iron compounds show different catalytic activities for their different dispersion on CZC and their different decomposition tendency to form active sites. Calcium compounds show different effects on NO emission depending on O-2 concentration. Ca(AC)(2) and CaCl2 increase NO emission under high O-2 concentration (such as 20.9%), but they decrease NO under low O-2 concentration (such as 1.2%). When CZC gasification under 4.8% O-2-Ar, Ca(AC)(2) decreases NO emission, but CaCl2 increases NO emission. (c) 2005 Elsevier Ltd. All rights reserved.