How to distinguish between China 6a and 6b?
2 Answers
Distinguishing between China 6a and 6b can be done by: 1. Different carbon monoxide emission levels; 2. Different non-methane hydrocarbon content; 3. Different nitrogen oxide content; 4. Different PM (particulate matter) levels. The China 6a emission standard stipulates that carbon monoxide emissions must not exceed 700 mg per kilometer, non-methane hydrocarbons must not exceed 68 mg per kilometer, nitrogen oxides must not exceed 60 mg per kilometer, and PM must not exceed 4.5 mg per kilometer. The China 6b emission standard requires carbon monoxide emissions to not exceed 500 mg per kilometer, non-methane hydrocarbons to not exceed 35 mg per kilometer, nitrogen oxides to not exceed 35 mg per kilometer, and PM to not exceed 3 mg per kilometer.
To distinguish between China 6A and China 6B, I think the most straightforward way is to check the vehicle nameplate or environmental certification, which usually clearly indicates the emission standard. I started learning about this when I bought a car last year, and the 4S store explained to me that China 6A is like a transitional version—for example, its nitrogen oxide limits are less strict than those of China 6B, which has more stringent requirements. Moreover, China 6B introduces real-world driving tests, meaning the vehicle must meet standards during actual driving, not just in lab tests, which puts more emphasis on the vehicle's durability and reliability. If you check the model year, most vehicles produced before 2020 are China 6A, while those produced later gradually shifted to China 6B. The implementation time varies by city—for example, the city I live in switched in 2020. You need to pay extra attention to this when buying a used car because China 6B vehicles have lower emissions, are more environmentally friendly, and this affects future inspections and resale value. I recommend all car owners check their documents or confirm with a repair shop—it saves money and gives peace of mind.
