What is the difference between National 4 and National 5 vehicles?
1 Answers
The differences between National 4 and National 5 vehicles are: 1. Different nitrogen oxide emission limits: National 4 vehicles have a nitrogen oxide emission limit of 0.25 grams per kilometer; National 5 vehicles have a nitrogen oxide emission limit of 0.18 grams per kilometer. 2. Different particulate emission concentrations: National 4 vehicles have a particulate emission concentration of 0.025; National 5 vehicles have a particulate emission concentration of 0.0045. National 4 and National 5 refer to the tailpipe emission standards set by environmental protection agencies, with higher numbers indicating relatively lower pollution levels in exhaust emissions. The National 5 standard is equivalent to the EU's Euro 5 standard, which imposes stricter limits on vehicle emissions such as nitrogen oxides, hydrocarbons, carbon monoxide, and particulate matter.