Mercedes-Benz engineers have developed BlueTEC, a filter system that almost completely purifies diesel emissions and already complies with the EU 6 exhaust standard (which does not come into force until 2014). This is possible thanks to a modular emission control system. In an initial processing stage, an oxidation catalytic converter and particulate filter reduce levels of carbon monoxide, hydrocarbons, particulate emissions and soot particles. In a subsequent step, the aqueous urea solution AdBlue® is sprayed into the exhaust gas. The heat splits the urea into ammonia molecules, which reduce nitrogen oxides in the downstream SCR catalytic converter by up to 90%. SCR stands for selective catalytic reduction. BlueTEC is available for the E 350 BlueTEC, ML 350 BlueTEC, GL 350 BlueTEC and R 350 BlueTEC.