What are the harmful gases emitted by cars?

[BrookeLynn]

Automobiles emit harmful gases such as carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, particulate matter (including certain heavy metal compounds, lead compounds, soot, and oil mist), and odors (formaldehyde). Vehicle emissions refer to the collective term for exhaust emissions, evaporative emissions, and crankcase emissions from automobiles, which is the abbreviation for harmful substances discharged and released by vehicles. To curb the generation of these harmful gases and encourage automobile manufacturers to improve their products to reduce the sources of these emissions, both Europe and the United States have established relevant vehicle emission standards. The European standards, in particular, serve as a reference for China's vehicle emission regulations. Currently, domestically produced new vehicles are required to indicate the European emission standards their engine exhaust meets.