The Order defines emissions requirements for the retrofit of Euro II, III, and IV base engines up to Euro III, IV, V, or EEV levels. In addition, retrofits to Euro III and IV levels require a minimum performance of
50% on PM and/or NOx reduction. Retrofits to Euro V and EEV require also a PM reduction >90% and/or NOx reduction >70%, according to the type of retrofit device installed. These efficiencies are to be measured
on the European Transient Cycle (ETC).
The Order also includes requirements on NO2 emissions. When the base engine NO2 emissions measured on the ETC exceed 0.8 g/kWh, the retrofit device should not increase this level. Otherwise, an NO2 limit of 0.8 g/kWh
applies after retrofitting. Also ammonia emissions, in the case of a DeNOx retrofit, need to comply with maximum levels allowed in appropriate Euro legislation. On 25th June 2014 the new UN Regulation concerning
the approval of Retrofit Emission Control devices (REC) for heavy-duty, agricultural and forestry tractors, and non-road mobile machinery equipped with compression ignition engines was published as UN Regulation
No 132.