In recent years, the European Union has issued directives such as Euro 4 & 5 which require significant reductions in Nitrous Oxide (NOx) emission from diesel engines. Beginning in 2010, the EPA will institute similar regulations for the North American market. To assure compliance with these new standards, several diesel engine manufacturers have implemented Selective Catalytic Reduction Systems (SCR) which injects AdBlue (AUS 32) to the vehicles emissions.