What does National III and National IV emission standards mean?
2 Answers
National III and National IV refer to exhaust emission standards. National III emission standard is the abbreviation for the third-stage national motor vehicle pollutant emission standard, while National IV emission standard is the abbreviation for the fourth-stage national motor vehicle pollutant emission standard. Compared to National III, National IV requires light-duty vehicles to reduce single-vehicle pollutant emissions by approximately 50%, heavy-duty vehicles to reduce single-vehicle emissions by about 30%, and particulate matter emissions by more than 80%. Automobile emission pollutants mainly include hydrocarbons, nitrogen oxides, carbon monoxide, and particulate matter. The National IV standard achieves control and reduction of vehicle emissions below specified levels through the application of technologies such as improved catalytic converter active layers, secondary air injection, and exhaust gas recirculation systems with cooling devices.
I recently researched this topic. The terms 'China III' and 'China IV' refer to vehicle emission standards. The China III standard was mainly implemented between 2007 and 2011, requiring vehicles to keep harmful substances like carbon monoxide and hydrocarbons below certain limits. The China IV standard, introduced around 2011, is even stricter - it reduced pollutant indicators by about 30% compared to China III and added testing requirements for nitrogen oxides and particulate matter. Nowadays during vehicle inspections, China III vehicles often fail due to excessive emissions, and many cities restrict China III diesel vehicles from entering urban areas. My own 2010 model car suffered from this - it failed last year's emission test, costing me nearly 2,000 yuan to fix.
