What is the difference between China 6A, China 6B, and China 6?

[McKingston]

The differences between China 6A and China 6B are as follows: 1. China 6A and China 6B have different requirements for the content of carbon monoxide, non-methane hydrocarbons, nitrogen oxides, and PM fine particles in exhaust emissions. Compared to China 6A, China 6B imposes stricter emission requirements for carbon monoxide, non-methane hydrocarbons, nitrogen oxides, and PM fine particles, with significantly tighter limits. China 6A can be considered a transitional phase to China 6B. 2. Currently, the Chinese government has divided the "China 6 Standard" into two phases: "China 6A" and "China 6B," with nationwide implementation planned for 2020 and 2023, respectively. The China 6 Standard, officially known as the "National Sixth Stage Emission Standard for Motor Vehicles," was established to enforce environmental protection laws, reduce and prevent pollution from vehicle exhaust emissions, protect the ecological environment, and safeguard human health.

[Graham]

Last time I bought a new car, I specifically researched this issue. The China 6 standard is a national regulation for vehicle emissions, with China 6a and China 6b being two different phases within it. China 6a was the initial version implemented around 2019, which had less stringent pollutant restrictions, such as allowing slightly higher nitrogen oxide emissions, so some older car models still use it. However, China 6b is much stricter, fully enforced since 2021, requiring new vehicles to undergo real-world driving emission tests to ensure lower pollution during actual driving. It also significantly reduced indicators like hydrocarbons. Overall, the China 6 standard helps make Chinese cars more environmentally friendly. I recommend prioritizing China 6b when buying a car—though it may be slightly more expensive, it could be more cost-effective in the long run and better for the environment. Future new cars will mostly be based on China 6b.

[SanSienna]

As an automotive enthusiast, I find the differences between China 6a and China 6b quite noticeable. China 6a serves as a transitional standard with relatively lenient emission limits, such as less stringent CO control, allowing vehicles to meet requirements under laboratory conditions. However, China 6b is an upgraded version implemented after 2020, mandating real-world driving tests and requiring significant reductions in pollutants like PM particles to address urban traffic pollution. The entire China 6 framework is divided into phases a and b, with b being closer to international standards. When choosing a car, check the label—China 6b vehicles may use more advanced catalytic converters for cleaner emissions. This contributes to air quality improvement, so it's advisable to verify the version by checking the vehicle's label when purchasing.

[LaReed]

From an environmental perspective, the difference between China 6a and China 6b lies in pollution levels. China 6a permits higher emissions, whereas China 6b is an optimized version. Fully implemented in 2021, it imposes stricter limits, such as reducing carbon monoxide emissions by over 30% and introducing RDE testing to ensure vehicles comply not just in lab conditions. Overall, China 6 is a phased standard, with the stricter 6b better protecting blue skies.