What are China's National I, II, III, IV, V, and VI Emission Standards?

[Jaxon]

China's National I, II, III, IV, V, and VI emission standards for vehicles are as follows: National I Standard: The National I standard is based on the Euro I standard, primarily setting limits for carbon monoxide, hydrocarbons, and particulate emissions. For example, carbon monoxide is limited to 3.16 grams per kilometer, and hydrocarbons to 1.13 grams per kilometer. Vehicles that meet the National I standard are classified as National I vehicles, and so on for the subsequent standards. National II Standard: Compared to National I, the National II standard reduces carbon monoxide emissions per vehicle by 30% and hydrocarbons and carbon oxides by 55%. National III Standard: The National III standard introduced an onboard diagnostic system and upgraded the three-way catalytic converter. It reduces total pollutant emissions by 40% compared to National II. National IV Standard: The National IV standard further upgraded the post-treatment emission system compared to National III, reducing pollutant emissions by 50% to 60%. National V Standard: Compared to National IV, the National V standard reduces nitrogen oxide emissions by 25% and adds restrictions on non-methane hydrocarbons and PM emissions, aiming to reduce air pollution and combat smog. National VI Standard: The National VI emission standard is 40% to 50% stricter than National V, surpassing even the Euro VI standard and being on par with U.S. standards, making it one of the most stringent emission standards worldwide.

[McRose]

I remember the evolution of China's vehicle emission standards, from National I to the current National VI. National I started around 2000 with very lenient limits, mainly regulating basic CO and HC pollutants. National II and III tightened significantly, implemented in phases from 2005 to 2008, adding some NOx controls, especially affecting diesel vehicles. Post-2010, National IV introduced OBD monitoring systems, preventing automakers from relying solely on lab tests to meet standards. National V in 2017 aligned strictly with Euro V, with much stricter limits. The recent National VI, divided into VIa and VIb, has caused quite a stir. VIa was implemented in 2020, while VIb is even stricter, requiring real-time on-road monitoring and reducing NOx and PM by over 90%. This not only improves air quality but also drives engine technology upgrades, making me prioritize National VI-compliant vehicles when changing cars.