How are vehicle emission standards classified?
2 Answers
Vehicle emission standards can be distinguished by the year of production: 1. Vehicles produced before 2011 are generally classified as China II or China III standards; 2. Vehicles produced between 2011 and 2018 are mostly classified as China IV or China V standards; 3. Vehicles produced in 2019 are generally classified as China VI standards. Vehicle emission standards refer to regulations on the content of harmful gases emitted from vehicle exhaust, such as carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM), and soot. The causes of these harmful gases vary: CO is an intermediate product of incomplete fuel oxidation and is produced when oxygen is insufficient. High fuel concentration and uneven fuel mixture can increase CO emissions. HC consists of unburned fuel components. NOx is a substance produced during the combustion process of fuel.
I found that automotive emission standards are primarily categorized by the restriction levels of pollutants. In China, they're called National Standards, ranging from National I to National VI, with higher numbers indicating stricter limits. The pollutants include harmful gases like carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The classification evolves with technological advancements: National IV already imposed strict CO controls, National V added NOx requirements, and National VI is divided into Stage VIa and VIb – with VIb even strictly limiting PM emissions. Driving in the city during smoggy days, I notice National VI vehicles emit much lighter exhaust compared to older cars' pungent fumes. These detailed standards aim for environmental protection, so checking the emission level is crucial when purchasing a car to avoid failing annual inspections. With the rise of new energy vehicles, fuel-powered vehicle standards may tighten further – I look forward to cleaner air.
