The paper consists of two parts. In the first part reported are the results of experimental physical characterization of a light duty IDI diesel engine exhaust particulate: concentrations, size distributions, and morphology. In the second part of the paper, presented is the development of a prototype particulate trap-oxidizer with ceramic foam as trapping element to reduce light-duty vehicle diesel engine exhaust particulate emission level. Tests of the trap-oxidiaer on the 485% diesel engine showed, ceramic foam trap reduced the diesel particulate emissions by 50-70% on the basis of mass concentrations. Trapped particulate deposits incinerates spontaneously when exhaust gas temperature over 450°C, reducing the resistance of the trap to exhaust flow. By the aid of fuel additives the regeneration temperature may he lowered by about 100°C.