New filters from the Siemens company Emitec remove as much as 80 percent of particulates from the exhaust gases produced by trucks. This represents a significant reduction of the pollutant emissions from this source. In addition to the filters, special catalytic converters ensure that the trucks meet exhaust-emissions limits. The system has been tested and optimized in cooperation with the truck manufacturer MAN. The latest engines from MAN already feature the combined filter-catalytic converter system. Similar retrofit systems are also available for passenger cars.