AdBlue® is a highly purified colourless liquid. It contains de-mineralized water and urea (32.5%). It is used with diesel engines and is also known outside of Europe as DEF, ARLA 32 or AUS 32 in some countries.
The main active component of AdBlue® is ammonia. This is chemically formed by hydrolysing automotive urea, which is the main raw material for AdBlue®. Urea is also used in the production of fertilizers and many more applications.
AdBlue® is used with diesel engines using SCR technology. This technology (Selective Catalytic Reduction) reduces harmful emissions (NOx). AdBlue® is injected into the catalyst of the SCR system, where it triggers a chemical reaction with the ammonia. This chemical reaction converts the toxic nitrogen oxides (NOx) into nitrogen (N2) and water vapour (H2O). Water vapour and nitrogen are naturally occurring gasses that are harmless to the environment.