What is the difference between Euro 5 and China 6?

[McMatthew]

Compared to the Euro 5 emission standard, the China 6 emission standard is more stringent, with China 6 becoming one of the strictest standards globally. Here are the relevant details: 1. The China 6 emission standard is an upgraded version of China 5, tightening the emission limits by nearly 50%, with the same requirements applying to diesel vehicles. 2. In specific terms, carbon monoxide emissions are reduced by 50% from the previous standard, with similar reductions for total hydrocarbons and non-methane hydrocarbons, while nitrogen oxide emissions are required to decrease by approximately 42%. 3. The Euro 5 standard was officially implemented in Europe in 2009 as the fifth-generation emission standard. Under Euro 5: the maximum particulate emissions are 0.005 grams per kilometer; total hydrocarbon emissions are below 0.1g/km; carbon monoxide emissions are below 1.0g/km; and nitrogen oxide emissions are below 0.06g/km.

[LailaLee]

Euro 5 is Europe's fifth-stage emission standard, while China 6 is China's sixth-stage emission standard, with significant differences in pollutant limits. China 6 reduces carbon monoxide limits from Euro 5's 1g/km to 0.5g, and nitrogen oxides from 0.06g to 0.035g, placing greater emphasis on reducing fine particulate emissions. The testing methods also differ: Euro 5 uses the old NEDC cycle, while China 6 adopts the new WLTC standard, which simulates real driving conditions like rapid acceleration to more accurately measure a vehicle's emissions in congested urban areas. This means vehicles must optimize engines and after-treatment systems, such as installing better filtration components. From an environmental perspective, China 6 is far stricter than Euro 5, helping China reduce air pollution and improve overall air quality, especially in smog-prone regions. Automakers must invest more in R&D, while consumers benefit from cleaner vehicles when purchasing new cars. Overall, this upgrade drives industry progress and makes vehicles more environmentally friendly.

[MartinAnn]

From a technical perspective, the differences between Euro 5 and China 6 are significant. China 6 imposes stricter particulate matter emission standards, reducing the non-methane hydrocarbon limit from 0.068 grams to 0.05 grams, requiring vehicles to use high-efficiency catalytic converters or particulate filters. Engine control has also been refined, with optimized fuel injection to avoid excessive emissions. In terms of testing, China 6 introduced Real Driving Emissions (RDE) tests, which were absent in Euro 5, enabling the detection of pollution levels at both high and low speeds and reducing manufacturers' opportunities for cheating. Vehicle designs have consequently undergone major changes, such as upgrading electronic systems in some China 6-compliant vehicles to monitor emission data in real time. For car owners, this may slightly increase maintenance costs, but in the long run, fuel efficiency becomes more stable. China 6 also covers more vehicle types, including electric vehicles, making the overall standard more advanced than Euro 5, reflecting China's efforts to catch up with global stringent trends.

[LeahLee]

The differences between Euro 5 and China 6 emission standards lie in implementation timelines and stringency. China 6 imposes stricter limits, such as nearly halving nitrogen oxide thresholds, and adopts the globally harmonized WLTC test cycle, which better reflects real-world driving conditions compared to Euro 5's NEDC. China introduced China 6 to address peak air pollution, launching later than Europe but with leapfrog stringent requirements that forced automakers to accelerate technological upgrades. For vehicles, China 6 mandates more sensitive onboard diagnostics (OBD) systems to promptly report malfunctions and prevent exceedances, whereas Euro 5 had weaker provisions. This impacts used car markets—China 6-compliant vehicles may retain higher residual value, but Euro-spec imports face tougher registration hurdles in China. Overall, China 6 drives industry transformation by significantly reducing tailpipe health hazards, representing a major regulatory advancement.