Exhaust gas facts for kids

This diesel-powered truck emits an exhaust gas rich in black particulate matter when starting its engine.

Exhaust gas is the smoky air that comes out when fuels like gasoline, diesel, or coal are burned. You often see it coming from car tailpipes, factory chimneys, or jet engines. It usually spreads out into the air, forming a cloud called an exhaust plume.

This gas is a major part of what cars and other engines release into the air. Vehicle emissions are a big cause of air pollution and create smog in many large cities. Research has shown that air pollution from vehicles can lead to health problems for many people.

What's in Exhaust Gas?

Most of the gas from burning fuel is made of things that aren't harmful on their own. These include nitrogen (N₂), water vapor (H₂O), and carbon dioxide (CO₂). While water vapor and carbon dioxide are not toxic, they are known as greenhouse gases that contribute to global warming.

However, a small part of exhaust gas contains substances that are not good for us. One example is carbon monoxide (CO), which can be harmful. Scientists are always looking for ways to make exhaust gas cleaner.

How Does Exhaust Gas Affect Us?

Exhaust gas can have effects on both our health and the local environment.

Health and Exhaust Gas

Scientists have studied how exhaust gas affects people's health. For example, some studies suggest that pollution from traffic might be linked to a small increase in the risk of certain health issues in children. Another study found that fumes from diesel engines can increase the risk of lung cancer. These studies help us understand why clean air is so important.

Local Effects of Exhaust Gas

In places like Southern California, studies show that more than half of the air pollution (smog) comes from car emissions. The amount of pollution can be very high in certain areas, like around busy intersections. This is because cars often sit still with their engines running (called idling) or speed up quickly, which makes them release more exhaust gas.

Images for kids

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  Steam from tailpipe of cold car

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  Automobile exhaust

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  What looks like exhaust from jet engines is actually contrail.

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  Smog in New York City as viewed from the World Trade Center in 1988

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  MOPITT satellite computer image of carbon monoxide March 2010

See also

In Spanish: Gas de escape para niños