What emission standard is China IV?
2 Answers
China IV is the China 4 emission standard. The China 4 emission standard is the national fourth-stage motor vehicle pollutant emission standard. The main pollutants emitted by vehicles include HC (hydrocarbons), NOx (nitrogen oxides), CO (carbon monoxide), and PM (particulate matter). By applying technologies such as improved catalytic converter active layers, secondary air injection, and exhaust gas recirculation systems with cooling devices, it controls and reduces vehicle emissions to below specified limits. Below is relevant information about toxic components in exhaust gases: 1. The causes of these harmful gases vary. CO is an intermediate product of incomplete fuel oxidation and is produced when oxygen is insufficient. High mixture concentration and uneven mixture distribution can increase CO emissions. 2. HC consists of unburned fuel materials, caused by uneven mixture distribution or cold combustion chamber walls, leading to some fuel being emitted before combustion. NOx is a substance produced during the combustion of fuel (gasoline). 3. PM is also a substance produced when fuel burns under oxygen-deficient conditions, most notably in diesel engines. Because diesel engines use compression ignition, diesel fuel is more likely to crack under high temperature and pressure, producing large amounts of visible carbon soot.
As a regular car owner, I paid attention to the China 5 emission standard when purchasing a vehicle two years ago. It represents China's fifth-stage vehicle pollutant emission regulations, which were fully implemented in 2017. Much stricter than China 4, it requires over 30% reduction in pollutants like carbon monoxide and hydrocarbons. I chose a new China 5-compliant car, noticing less pungent exhaust and the ability to enter urban centers—unlike China 4 vehicles facing driving restrictions. The salesperson mentioned that China 5 cars require higher-octane gasoline, slightly increasing costs but benefiting the environment long-term, especially by reducing particulate emissions during traffic jams. Now with China 6 in effect, standards are even stricter, but my China 5 car runs fine daily and passes annual inspections easily. When buying a car, it's best to check the emission level to avoid future hassles.
