What is the difference between National 4 and National 5 vehicle emission standards?

[McMaya]

The specific differences between National 4 and National 5 vehicle emission standards are as follows: 1. Different limits on vehicle exhaust emissions: Compared with National 4 standards, the National 5 standards can reduce nitrogen oxide emissions from light-duty vehicles by 25% and from heavy-duty vehicles by 43%. It can be seen that the biggest difference between National 5 and National 4 lies in stricter emission requirements for heavy-duty vehicles. Additionally, the standards for nitrogen oxides (NOX), the sum of hydrocarbons and nitrogen oxides (HCNOX), and particulate matter concentration (PM) have been raised. Furthermore, National 5 has introduced standards for particulate matter particle count (PN) and non-methane hydrocarbons (NMHC). The National 5 standard is comparable to the currently implemented European Stage 5 emission standard in terms of control level. 2. Different information on environmental labels: The emission limits specified on National 4 environmental labels are more lenient than those on National 5 labels.