AdBlue is the registered trademark of the Verband der Automobilindustrie (VDA) for high purity aqueous urea solution (32.5%) for use in selective catalytic reduction systems (SCR) to reduce emissions from Diesel Vehicles.

The AdBlue is stored in a separate tank on the vehicle and from there is dosed automatically into the exhaust gas, as required to the amount of Nitrous Oxides (NOx) being produced by the engine. 

Following the dosing, the exhaust gas and AdBlue mixture passes through the SCR system where a chemical reaction takes place, converting the harmful NOx to harmless nitrogen and water which is dispersed from the end of the exhaust

AdBlue is non-toxic and safe to handle. It is not a fuel or a fuel additive and should only be used in the dedicated tank in your vehicle. It is refilled in a similar way to refuelling diesel.

SCR technology is being adopted by most large scale car manufacturers for new diesel engine vehicles and is becoming more widely available in petrol stations and by oil suppliers.

How much to use

Average consumption of AdBlue® in Heavy Goods Vehicles and Buses is approximately 5% of diesel use.

Average consumption in cars and light vehicles is approximately 1 litre of AdBlue® for every 1000 Kilometre driven.

These are just average consumption guidelines and the actual use will depend on the make and model of the vehicle and the driving style. The amount of AdBlue consumed is directly proportional to the amount of diesel used, so driving more economically will consume less AdBlue along with less diesel.