What are the symbols for China's emission standards?

[AutumnLee]

China's vehicle emission standards are denoted as China I, China II, China III, China IV, China V, and China VI. The purpose of these emission standards is to implement environmental protection laws, reduce and prevent vehicle exhaust pollution, protect the ecological environment, and ensure human health. Below is a detailed introduction to China's vehicle emission standards: China I Emission Standard: In the early 1980s, China issued a series of motor vehicle exhaust pollution control emission standards, including the "Idle Emission Standard for Gasoline Vehicles," "Free Acceleration Smoke Emission Standard for Diesel Vehicles," "Full-Load Smoke Emission Standard for Automotive Diesel Engines," and their measurement standards. This marked the gradual establishment of China's vehicle emission standards. The China I standard was fully implemented nationwide on July 1, 2001. China II Emission Standard: By this stage, China had developed a relatively complete vehicle exhaust emission standard and testing system. Beijing was the first to implement the China II emission standard. The requirements for various pollutant emissions were further tightened, and the standard was implemented nationwide by July 1, 2004. China III Emission Standard: On December 30, 2005, Beijing began implementing the China III emission standard. It was also during this time that OBD devices started to be widely used. The specific implementation dates were: July 1, 2009, for light-duty diesel vehicles; July 1, 2010, for heavy-duty gasoline vehicles; July 1, 2008, for heavy-duty gas vehicles; and July 1, 2008, for heavy-duty diesel vehicles. China IV Emission Standard: On January 1, 2008, China IV fuel was introduced in Beijing, followed by the implementation of the China IV standard in multiple cities such as Beijing, Shanghai, and Guangzhou. The nationwide implementation dates were: July 1, 2013, for light-duty diesel vehicles; July 1, 2013, for heavy-duty gasoline vehicles; January 1, 2011, for heavy-duty gas vehicles; and July 1, 2013, for heavy-duty diesel vehicles. China V Emission Standard: The China V emission standard was fully implemented nationwide on July 1, 2017. Compared to China IV, it reduced nitrogen oxide emissions by 25% and introduced stricter PM emission limits. China VI Emission Standard: The "China VI" standard is an upgrade of the China V standard. Compared to "China V," "China VI" imposes stricter limits on pollutant emissions, making it one of the most stringent standards globally. Specifically, "China VI" reduces carbon monoxide emissions from gasoline vehicles by 50%, total hydrocarbon and non-methane hydrocarbon emission limits by 50%, and tightens nitrogen oxide emission limits by 42%.