What is the difference between China 6a and China 6b?
2 Answers
The differences between China 6a and China 6b are: 1. Different carbon monoxide emission limits: China 6a must not exceed 700 mg per kilometer; China 6b must not exceed 500 mg per kilometer. 2. Different non-methane hydrocarbon emission limits: China 6a must not exceed 68 mg per kilometer; China 6b must not exceed 35 mg per kilometer. 3. Different nitrogen oxide emission limits: China 6a must not exceed 60 mg per kilometer; China 6b must not exceed 60 mg per kilometer. 4. Different PM particulate matter emission limits: China 6a must not exceed 4.5 mg per kilometer; China 6b must not exceed 3 mg per kilometer.
China 6a and China 6b are both China's vehicle emission standards, just upgraded versions. China 6a can be considered the early stage, mainly implemented from 2019, with stricter limits on harmful gases in exhaust, such as halving carbon monoxide and nitrogen oxides. However, the testing method back then was still the old NEDC, not very realistic. By China 6b, which became mandatory after 2020, the emission standards were lowered further, requiring fewer particulates, and new testing methods like WLTC were adopted, simulating real-road driving, making it more reliable. As a car owner, I feel more at ease choosing a China 6b vehicle, especially in big cities with poor air quality—it's fuel-efficient and eco-friendly. However, China 6b comes with higher costs; new cars might be more expensive, while used China 6a cars are cheaper, so you need to choose according to your needs. Overall, China 6b is progress, better for the environment, and the country is pushing it quite actively.
