How are vehicle emission standards classified?

[LaTalia]

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.

[McXavier]

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.

[StAna]

As a car enthusiast, I understand that the classification of emission standards is quite straightforward: the higher the number, the cleaner the standard. From China 1 to China 6, each stage has lower limits. The main pollutants include CO, HC, NOx, and PM. The classification is updated through regulations; during China 6, it was divided into A and B, with A being a transitional phase and B being the true standard. I've driven different cars, and a China 5 vehicle emits at least 30% less exhaust than a China 3 one, and the acceleration is smoother. This grading system helps automakers develop new engines—for example, my SUV is designed for China 6 standards and is more fuel-efficient. A related point is that these standards affect used car prices, as a China 4 vehicle might be restricted from entering urban areas. When choosing a car, don’t just focus on appearance; the emission level is crucial for long-term use.

[JuliaLynn]

Back when I bought my first car, I learned that emission standards are divided into several tiers. Roughly from the lowest National I to the latest National VI, they've become progressively stricter, like software updates for phones. What pollutants are there? I remember toxic gases like carbon monoxide being included. The classification is customized based on testing data; after National V, many new test items were added, and National VI was rolled out in two phases, called VIa and VIb. When choosing a car, I go for National VI to avoid it being banned from the roads in a few years. Fuel prices are also related—higher standards may require premium fuel, which costs more but improves air quality. Simply put, higher tiers mean more eco-friendliness, which significantly impacts daily commuting.

[VanNolan]

I find the classification of automotive emission standards quite practical. From China 1 to China 6, each level represents stricter limits on pollutants such as nitrogen oxides and particulate matter. The classification is based on progressively refined policies; China 6 was further divided into VIa and VIb because automakers needed a transition period. As someone who drives family members around, I care about health impacts; China 5 vehicles emit less exhaust, while China 6 ones are almost smokeless. This classification drives technological innovation and may slightly reduce maintenance costs. Additionally, the government promotes electrification to address gaps, so I prioritize China 6 when choosing a car—it's safer and more worry-free.