Due to their design, diesel engines emit nitrogen oxides, which are largely responsible for the depletion of the ozone layer. In order to reduce emissions of this climate-damaging gas, maximum limits have been set by legislation and defined in the well-known EURO 5 and EURO 6 standards. In order to comply with these limits, many modern diesel engines inject AdBlue® (urea solution) directly in front of the SCR catalytic converter to convert around 90% of the climate-damaging nitrogen oxide into harmless nitrogen and water.