Particulate Matters (PM) are known to be dangerous to human health and the environment. Regulations have been set to limit PM levels from vehicles, including compression ignition engine vehicles. The effect of increasing biodiesel content in the fuels has been investigated with respect to the PM using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). PM from tire emissions were compared against diesel PM using SEM, energy dispersive x-ray spectroscopy (EDS), TEM, particle size analysis, x-ray diffraction (XRD), and Raman spectroscopy (RS). The SEM and TEM show that increasing the biodiesel content decreased the size of the PM agglomerate particles, primary particles, and fringes. The EDS, RS, and XRD show that Tire PM are mostly carbon with silicon, calcium, zinc, and other various trace elements. They also allow comparisons with diesel PM for the carbon nanostructure. The particle size analysis shows that Tire PM are generally larger than engine derived PM. The TEM showed that the nanostructure of the carbonaceous Tire PM was the same fringe structure as the engine derived PM. The Tire PM was successfully characterized using similar methods as engine derived soot. There is strong relationship between the increasing of biodiesel content and reduction of agglomerate size, primary particle size and average fringe length.