AdBlue®, a water/urea based additive, is stored in a tank (like diesel fuel), however, unlike fuel it is not injected into the engine, but directly into a specially modified part of the vehicle’s exhaust. This begins a chemical reaction which removes the polluting oxides of nitrogen (NOx), converting them into harmless oxygen and nitrogen in a process known as Selective Catalytic Reduction, or SCR for short. SCR is only applicable to diesel engines and the more economically you drive, typically, the less AdBlue® you will use.

The size of the AdBlue® tank fitted to your car will vary depending on which model you have, therefore the interval between top-ups will vary. In addition, many factors such as mileage, journey type, driving style and environmental conditions can influence how much AdBlue® is consumed. A passenger car can consume approximately 1.5 litres of AdBlue® every 620 miles.