In this study, the effects of lubricating oil additive diesel fuel on the diesel engine emission particles characterizations, such as size distribution, morphology, nanostructure and composition was investigated on a light-duty diesel engine. Fast particle spectrum analysis was used for the determination of size distribution, and transmission electric microscopy (TEM) technique for the investigation of morphology of particles. On the other hand, the element carbon fraction can be obtained through thermogravimetric analysis (TGA). Compared with the emission particles from burning pure diesel fuel, the emission particles from burning lubricating oil additive diesel fuel have lower fractal dimension. Measurement results of the nanostructure parameters show that emission particles from burning oil additive dosed fuel have lower graphite structure than those from burning pure diesel fuel. TGA results indicate that more volatile and ash fraction were contained in the particles when oil additive was mixed into diesel. In conclusion, the oil additive may increase the nucleation mode particles and ash component. Therefore, the enhanced performance of diesel particulate filter (DPF) system may be required. Thus, the usage of oil additive should be optimized by considering the tradeoff between oil quality and particle emissions contribution. (C) 2014 Elsevier Ltd. All rights reserved.