What does exceeding vehicle exhaust emission limits mean?

[StKevin]

Vehicle exhaust emission standards in China comply with the National IV standard. Below are the harmful substances in vehicle exhaust and their hazards: Harmful substances in vehicle exhaust: Vehicle exhaust contains hundreds of different compounds, including pollutants such as particulate matter, carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides, lead, and sulfur oxides. Hazards of vehicle exhaust: While directly endangering human health, exhaust emissions also have profound impacts on the environment. Sulfur dioxide in exhaust has a strong irritating odor and, when reaching certain concentrations, can easily lead to "acid rain," causing soil and water acidification and affecting the growth of crops and forests.