The presence of a NOx trapping BaO component with a Pt active phase does not per-se promote carbon combustion. However when coupled with trap regeneration, promotion of soot combustion is seen. Operating NO, trapping materials promote combustion due to the periodic localised increases in [NO2]((g)) generated during the regeneration rather than due to a co-generated exotherm. However, it has been noted that the presence of soot prevents NOx traps from employing their full trapping capacity. (c) 2007 Elsevier B.V. All rights reserved.