What Are the Pass Standards for Vehicle Exhaust Emissions Testing?
2 Answers
National V exhaust emission testing data standards: CO, THC, NMHC, NOx, and PM are 1.00g/km, 0.100g/km, 0.068g/km, 0.060g/km, and 0.0045g/km respectively. The hazards of vehicle exhaust emissions are as follows: 1. Scientific analysis shows that vehicle exhaust contains hundreds of different compounds, including pollutants such as solid suspended particles, carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides, lead, and sulfur oxides. A car emits three times its own weight in harmful exhaust gases each year. The British Society for Clean Air and Environmental Protection once published a research report stating that the number of people who die from air pollution in the UK each year is 10 times higher than those who die in traffic accidents. 2. While directly harming human health, exhaust emissions also have a profound impact on the environment. Sulfur dioxide in exhaust has a strong irritating odor and, at certain concentrations, can easily lead to "acid rain," causing soil and water acidification and affecting the growth of crops and forests. Over the past 100 years, the greenhouse effect has become a major scourge for humanity. Melting glaciers, rising sea levels, El Niño, and La Niña phenomena have all posed extremely severe challenges to human survival, with carbon dioxide being the main culprit behind the greenhouse effect.
Actually, there's no fixed value for exhaust emission standards—it depends on the year and model of your car. For gasoline vehicles, the main tests are for carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). For example, for China IV standard vehicles purchased after 2011, the CO level at idle should not exceed 0.7%, and HC must be below 100 ppm. For China V standard vehicles purchased after 2017, the requirements are even stricter, with NOx levels needing to be below 800 ppm. Diesel vehicles mainly focus on smoke concentration—older vehicles with an opacity exceeding 3.0 m⁻¹ may fail, while newer vehicles should keep it under 2.5 m⁻¹ to pass. Before testing, it's recommended to warm up the engine for 20 minutes to heat up the catalytic converter, which can significantly improve the pass rate.
