What are the main pollutants emitted by vehicles?

[SanCassidy]

Here is an introduction to vehicle emission pollutants: 1. Carbon monoxide: Carbon monoxide is an intermediate product of hydrocarbon fuel combustion. The presence of CO in exhaust is caused by incomplete combustion of hydrocarbons. CO is a colorless, non-irritating gas. Among the harmful components in vehicle and internal combustion engine exhaust, carbon monoxide has the highest concentration. It has an extremely strong affinity with hemoglobin in human blood. After inhaling CO, the blood loses its ability to transport oxygen, hindering human metabolism and causing hypoxia-induced asphyxiation. 2. Hydrocarbons: The HC in exhaust consists of unburned fuel hydrocarbons, incomplete oxidation products, and partially decomposed products from the combustion process.

[StAlivia]

As an ordinary person who drives frequently, I pay close attention to vehicle exhaust issues. The main pollutants include carbon monoxide, which is produced when gasoline doesn't burn completely—it's colorless and odorless but can cause dizziness or even suffocation. Then there are nitrogen oxides, which react with sunlight and air to form that hazy smog, especially noticeable on bad weather days. Additionally, particulate matter like PM2.5 particles can float in the air and be inhaled into the lungs, affecting respiratory health. Volatile organic compounds such as benzene, a carcinogen, are present in gasoline fumes. Lastly, sulfur dioxide, though emitted in small amounts, can contribute to acid rain. I've personally seen older cars with excessive emissions, and when I took it for repairs, the mechanic said the catalytic converter was broken and needed prompt replacement. Regular vehicle maintenance can reduce these pollutants—cleaner air means safer driving for everyone. Fresh air benefits us all, making this a simple yet effective way to live greener.

[OHarper]

As an environmental enthusiast, I am deeply aware of the significant environmental damage caused by vehicle emissions. The main pollutants include carbon monoxide, which exacerbates the greenhouse effect; nitrogen oxides, which form ozone layer holes at high altitudes and lead to acid rain that harms trees; volatile organic compounds like toluene, which can transform into ground-level ozone causing respiratory diseases; particulate matter such as PM10, which accumulates in urban air and worsens smog; and hydrocarbons, which pollute water sources and soil. Seeing children frequently coughing in polluted areas, I want to advocate for everyone to drive electric vehicles or carpool. New energy vehicles are now popular, emitting much less pollution, and the government is also pushing for stricter emission standards. Protecting the Earth starts with reducing exhaust emissions—small changes by each person can make a big difference in the world.

[Alexis]

From a technical automotive perspective, engine combustion generates several common pollutants. Carbon monoxide forms due to insufficient oxygen; nitrogen oxides result from the reaction between nitrogen and oxygen at high temperatures; volatile organic compounds such as hydrocarbons are released from fuel evaporation and unburned gases; particulate matter mainly consists of soot, which modern engine designs can control for emissions. Catalytic converters are highly effective at filtering exhaust gases, and it is recommended that vehicle owners maintain their engines regularly. This helps reduce harm to the air.