How to Identify China 6a or China 6b?
3 Answers
China 6b has not been officially implemented yet. Currently, vehicles on the market that comply with the China 6 standard generally meet the China 6a specifications. 1. The China 6a standard specifies the following: The carbon monoxide emissions per kilometer driven by a gasoline vehicle must not exceed 700 milligrams. The non-methane hydrocarbon emissions per kilometer driven by a gasoline vehicle must not exceed 68 milligrams. The nitrogen oxide emissions per kilometer driven by a gasoline vehicle must not exceed 60 milligrams. The PM (particulate matter) emissions per kilometer driven by a gasoline vehicle must not exceed 4.5 milligrams. 2. The China 6b standard specifies the following: The carbon monoxide emissions per kilometer driven by a gasoline vehicle must not exceed 500 milligrams. The non-methane hydrocarbon emissions per kilometer driven by a gasoline vehicle must not exceed 35 milligrams. The nitrogen oxide emissions per kilometer driven by a gasoline vehicle must not exceed 35 milligrams. The PM (particulate matter) emissions per kilometer driven by a gasoline vehicle must not exceed 3 milligrams.
I recently researched this issue when changing cars, and the key to identifying China 6a or China 6b lies in checking the vehicle's documentation. Typically, the salesperson provides an environmental information sheet during purchase, which clearly states the emission standard code—if it's China 6b, it will be labeled as 'GB18352.6-2016b'. Another quick method is to open the hood or check the small label on the door frame, such as in the engine compartment or the corner of the windshield, where similar information can be found. This is how I confirmed my newly purchased car is China 6b, which is stricter than China 6a with much better particulate control and less impact on air pollution. Pay extra attention to this detail when buying a car, especially since traffic restriction policies in some major cities now vary significantly, and second-hand prices for China 6a vehicles are considerably lower than those for 6b—this helped me save a lot on my budget.
In practice, I usually help others determine the emission standards in a simple way, such as directly checking the environmental section on the vehicle compliance certificate or registration document. If there are no paper documents, you can download some official apps on your phone and enter the VIN code to check. China 6a typically applies to models around 2019, while China 6b is the common standard after 2020. The difference lies in the lower nitrogen oxide limits of China 6b, which reduces carbon buildup issues during daily driving and lowers long-term maintenance costs. I always advise car owners to confirm this first to avoid trouble, as it affects annual inspection pass rates and even daily emission tests.
