The newest EU standard and current incarnation for cars and light commercial vehicles is Euro 6, which was introduced for new type approvals in September 2014 and for all new cars in September 2015.
For diesels, the permitted level of NOx has been slashed from 0.18g/km in Euro 5 to 0.08g/km.
A focus on diesel NOx was the direct result of studies connecting these emissions with respiratory problems. To meet the new targets, some carmakers have introduced Selective Catalytic Reduction (SCR), in which AdBlue is injected through a catalyst into the exhaust of a diesel vehicle. A chemical reaction converts the nitrogen oxide into harmless water and nitrogen, which are expelled through the exhaust pipe.
Legislation for Transportation vehicles
Heavy-duty vehicles like trucks and buses have their own standards, with the latest being Euro VI, first enacted in December 2013.
Euro 6 came into force in 2014. It will especially affect standards for diesel driven vehicles, requiring further reduction of NOx and Hydrocarbon emissions. Consequently, it has meant that the majority of commercials required SCR system and AdBlue® has become vital to meet the Euro 6 standards.
Non-road mobile machinery directives
SCR technology is also widely used in non-road mobile machinery (NRMM) that uses diesel-powered engines. This varied category of vehicles includes such things as generators, construction machinery, forklifts and mobile cranes.
These engines are subject to a separate EU directive to road-going vehicles: Directive 97/68/EC, which was first introduced in 1999 and the regulations only apply to new engines in NRMM.
As the limits became more stringent with each passing amendment, it became clear that SCR technology was the best technology to achieve the targets. This has meant that AdBlue® has become an essential product for NOx emission control to the industry.
Agricultural tractors and machinery were subject to regulations laid out in EU directive 2000/25/EC. Here a series of progressively more stringent requirements for the emissions of noxious pollutants from the exhausts of new tractors. In 2019 Stage V came into force, and is currently still the relevant legislation for newly manufactured vehicles.
This new standard updated the previous ones and incorporated new lower limits for agricultural vehicles into the wider NRMM standards. The lower limits require agricultural machinery manufacturers to make use of SCR technology, as well as Exhaust Gas Recirculation (EGR) and Diesel Particulate Filters (DPF), which can also help to lower NOx and particulate matter (PM) levels in emissions.