What are the differences between China 5 and China 6 vehicle emission standards?

[OReid]

The differences between China 5 and China 6 emission standards are as follows: Different emission standards: China 6 standards are more than 30% stricter than China 5. Excluding the influence of working conditions and testing, gasoline vehicles' carbon monoxide emissions are reduced by 50%, total hydrocarbons and non-methane hydrocarbons emissions are reduced by 50%, and nitrogen oxide emissions are reduced by 42%. Different implementation times: The China 5 standard was implemented nationwide on January 1, 2017. China 6 has been implemented since July 1, 2019. Different principles: During the China 5 phase, diesel and gasoline vehicles had different emission standards, but China 6 adopts a fuel-neutral principle, meaning the emission limits are the same regardless of the fuel type. Different issuing authorities: The China 5 standard was issued by the Ministry of Environmental Protection. The China 6 standard was issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection and Quarantine. Different letter representations: China 5 is represented by "V"; China 6 is represented by "VI". Different monitoring requirements for plug-in hybrid electric vehicles: Compared to China 5, China 6 has improved monitoring requirements for plug-in hybrid electric vehicles, including energy storage systems, thermal management systems, brake regeneration, drive motors, generators, and other regulations. China 5 standard limits are as follows: Gasoline vehicles must not emit more than 1,000 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 68 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 60 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 4.5 milligrams of PM fine particles per kilometer driven. China 6 has two standards: China 6a and China 6b. The details are as follows: China 6a standard limits: Gasoline vehicles must not emit more than 700 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 68 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 60 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 4.5 milligrams of PM fine particles per kilometer driven. China 6b standard limits: Gasoline vehicles must not emit more than 500 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 35 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 35 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 3 milligrams of PM fine particles per kilometer driven. Affected by the China 6 emission policy, although China 5 vehicles are not currently restricted in normal use, their resale value is significantly impacted. For truck owners, if they purchase a truck on loan for hauling goods, the depreciation of the vehicle after paying off the loan is equivalent to the net profit earned during that period. A higher residual value means more profit for the owner. Therefore, from this perspective, China 6 vehicles, which have a longer service life and more road rights, are more advantageous.

[DiFernando]

I've recently done specialized research on emission standards, and the main differences between China 5 and China 6 lie in pollution control. The China 6 standard is much stricter, with a 30% reduction in carbon monoxide limits compared to China 5, and the addition of real-world driving emission testing requirements, where tailpipe emissions must be measured while driving. The most critical change is the introduction of particulate matter quantity limits, which weren't measured at all under China 5. Technologically, China 6 vehicles are also different, as they mostly come equipped with particulate filters, and their engine control strategies have been recalibrated. Additionally, China 6 is divided into two phases, a and b, with phase b being even stricter but requiring better three-way catalytic converters. Currently, China 6 vehicles cost a few thousand yuan more, but you won't have to worry about traffic restrictions or obsolescence for seven or eight years, making them quite worthwhile in the long run.

[McJosephine]

When repairing cars, customers often ask about the differences between China 5 and China 6 emission standards. Simply put, China 6 vehicles have cleaner exhaust pipes but much more complex systems. The China 6 engine ECU has an additional sensor to monitor exhaust emissions, and the fuel tank is redesigned to be sealed to prevent gasoline evaporation. The three-way catalytic converter is significantly more expensive, as it requires precious metal coatings to meet the standards. The most troublesome part is the diesel particulate filter (DPF), which tends to clog easily and requires high-speed driving to regenerate. Currently, most major cities no longer allow China 5 vehicles to be transferred, making China 6 vehicles retain their value much better. It's recommended to directly purchase China 6b-compliant models when buying a new car to avoid future depreciation issues.

[LeoDella]

Understanding the difference between China 5 and China 6 emission standards is crucial when buying a car. The most practical impact of China 6 standards on car owners is the license plate restrictions—major cities like Beijing, Shanghai, Guangzhou, and Shenzhen stopped issuing new plates for China 5 vehicles long ago. In the used car market, China 6-compliant vehicles can be traded nationwide, while China 5 vehicles may face hurdles in cross-city transfers. When refueling, remember that China 6 cars require China 6-standard gasoline; otherwise, the particulate filter will likely trigger an alarm. The implementation of China 6 standards occurred in two phases: the 6a introduced in 2020 was transitional, while the stricter 6b, enforced nationwide in 2023, represents the real deal. Currently, buying a used China 5 car may be cheaper but carries higher risks, as sudden driving restrictions could be imposed at any time.

[AlexanderAnn]

From a user's perspective, there isn't much difference in driving between China 5 and China 6 vehicles, but the long-term impacts are significant. The China 6 standard has more comprehensive pollution controls, regulating not just nitrogen oxides but also ammonia and ozone emissions. Our gas station's fuel quality has been upgraded accordingly, with low-sulfur gasoline being supplied since last year. Although China 6 vehicles are slightly more expensive, they pass annual inspections more easily. Indeed, the number of hazy days on the road has decreased, and even the elderly in our neighborhood are coughing less. However, it's worth noting that China 6 vehicles require a longer warm-up time during cold starts to allow the catalytic converter to heat up quickly.

[DelGavin]

China 5 and China 6 are essentially steps in environmental protection upgrades. The biggest change in China 6 is the testing method, which includes not only laboratory tests but also RDE real-world driving emission tests. It's particularly strict for diesel vehicles, with PM particulate limits reduced to one-third of China 5 standards. Most new cars sold now are at the China 6b stage, requiring even special treatment for crankcase ventilation. Interestingly, China 6 vehicles are more fuel-efficient due to optimized combustion efficiency. However, post-maintenance requires attention, as replacing a three-way catalytic converter can cost three to four thousand yuan. Traffic restriction policies also vary by region; for example, Hebei still allows China 5 vehicles, but entering Beijing's Sixth Ring Road requires a China 6 vehicle.