Particulate matter filters--also referred to as Diesel Particulate Filters, or DPFs--are one of the after treatment products available from Michigan CAT Emissions Solutions to lower emissions from the in-use population of diesel engines. PM Filters are used primarily to reduce PM, CO, and HC from diesel engine exhaust through catalytic oxidation and filtration. These filters are self-regenerating, which means they do not need to be replaced, but, instead, will "burn off" the accumulated soot periodically. For proper regeneration, the exhaust temperature must exceed 260 degrees C at least 40% to 50% of the time and the sulfur content of the diesel fuel must not exceed 50 ppm. PM Filters can reduce PM, CO and HC by 80% to 90%.