What is the difference between National 5 and National 6?
1 Answers
The difference between National 5 and National 6 lies in their emission control levels: National 5 emission control level is equivalent to the European Union's currently implemented Stage 5 emission standard; National 6 emission standard aims to prevent environmental pollution caused by exhaust emissions from compression-ignition and gas-fueled spark-ignition engine vehicles. The National 6a phase emission standards are basically the same as National 5, adopting the strictest values from National 5 requirements. For example, National 5 stipulates that carbon monoxide emissions from gasoline vehicles must not exceed 1g, while diesel vehicles must not exceed 0.5g. Under National 6a, both vehicle types must not exceed 0.5g in carbon monoxide emissions. According to online information, the National 6 standard is divided into two phases, with different implementation times depending on specific circumstances.