Diesel particulate filters (DPF) are machinery that physically capture diesel particles in order to keep them from being released into the environment. Materials for diesel particle filters have been developed that exhibit strong mechanical and thermal endurance as well as outstanding filtering efficiency, in excess of 90%. The most effective technique for reducing diesel particulate emissions, including particle mass and number, is now diesel particulate filters, which also have excellent efficiency.

Filters are particularly efficient in controlling the solid portion of diesel particles, including elemental carbon (soot) and the associated emission of black smoke, due to the particle deposition processes in these devices. The organic fraction (OF) and sulphate particles, which make up the non-solid components of PM emissions, may be just partially or completely unaffected by filters. While extremely low sulphur fuels may be necessary to manage sulphate particles, DPF systems are likely to contain additional functional components targeting the OF, generally oxidation catalysts, to limit overall PM emissions.