For many people, the Euro standards are becoming more stringent. For you they are more cost-effective.
There is an economical solution to ensure Euro 4 and Euro 5 compliance: BlueTec®, the Mercedes-Benz SCR diesel technology. This technology employs a catalytic converter to reduce nitrogen oxide emissions. The process is assisted by the additive AdBlue, which is supplied from a separate tank. Thanks to SCR diesel technology (selective catalytic reduction), Mercedes-Benz satisfies Euro emissions standards and reduces exhaust emissions and fuel consumption. Some engines (410 & 440 hp) even support the EEV standard.