What is the difference between China 6a and 6b?
2 Answers
Here is an introduction to the differences between China 6a and China 6b: 1. For light-duty vehicle emission limits, the country has set two levels of requirements this time: the "China 6a" phase and the "China 6b" phase. "China 6a" is equivalent to a transitional stage between "China 5" and "China 6", while "China 6b" is the true "China 6" emission standard. 2. The emission standards for the "China 6a" phase are basically the same as those for "China 5", only taking the strictest values from the "China 5" emission requirements. The control of particulate emissions from vehicle exhaust has been tightened from 6*10^12 to 6*10^11. The emission standards for China 6b are almost twice as strict as those for "China 6a", and a more stringent "Real Driving Emissions (RDE) test" is adopted.
China 6a and China 6b are both sub-stages of China's Phase VI emission standards, but there are significant differences between them. As a transitional standard, China 6a has relatively lenient limits on nitrogen oxides and carbon monoxide, and was implemented earlier, starting in 2019 for example. China 6b is much stricter, with significantly lower pollutant limits, and requires testing under more real-world driving conditions, including different temperature ranges, to ensure compliance whether the vehicle is hot-started or cold-started. Simply put, China 6b is more environmentally friendly and has more comprehensive requirements, representing the ultimate goal. For us drivers, choosing a China 6b-compliant vehicle means less pollution and more reliable performance in the long run. From a car-buying perspective, many new models on the market now directly meet China 6b standards, and I recommend prioritizing them to avoid potential impacts on resale value due to future policy adjustments. Overall, China 6a was a buffer period for automakers, while China 6b represents the real environmental upgrade.
