What does China IV mean?

[VanGia]

China IV is the China 4 standard, represented by Roman numerals where I, II, III, IV, V, VI correspond to 1, 2, 3, 4, 5, 6 respectively. The China IV emission standard refers to the national fourth-stage motor vehicle pollutant emission standard. The main pollutants emitted by vehicles include HC, NOx, CO, PM, etc. The implementation of the China 4 standard aims to control and reduce vehicle pollutant emissions, keeping them below specified limits to protect the country's atmospheric environment and minimize harm to human health. After the implementation of the China IV emission standard, it requires a reduction of vehicle pollutant emissions by approximately 50% compared to the China III standard, with heavy-duty vehicle pollutant emissions reduced by about 30% and particulate matter emissions lowered by around 80%.