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Auto | Under the Hood | Exhaust & Emissions

This section can help you keep your exhaust system working properly. Learn how mufflers, catalytic converters and oxygen sensors work.

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Top 7 Ways to Reduce Your Driving Emissions without Reducing Quality of Life

Here are seven easy ways to reduce your emissions without affecting the quality of your daily commute. Learn more about the top 7 ways to reduce your driving emissions without reducing quality of life.


How Coal Rollers Work

How Coal Rollers Work

Coal rollers create plumes of black smoke by forcing more fuel into a diesel engine than it can handle. Learn about coal rolling at HowStuffWorks. See more »

How much air pollution comes from cars?

How much air pollution comes from cars?

How much air pollution comes from cars? Keep reading to learn about air pollution and how much comes from cars. See more »

Top 7 Ways to Reduce Your Driving Emissions without Reducing Quality of Life

Here are seven easy ways to reduce your emissions without affecting the quality of your daily commute. Learn more about the top 7 ways to reduce your driving emissions without reducing quality of life. See more »

What can you do to reduce your car's emissions?

What can you do to reduce your car's emissions? Visit HowStuffWorks.com to learn how to reduce your car's emissions. See more »

The Catalytic Converter Quiz

The Catalytic Converter Quiz

The catalytic converter quiz will test your knowledge of catalytic converters and how they work. Take the catalytic converter quiz. See more »

Can we make tailpipes that capture CO2?

Can we make tailpipes that capture CO2?

Tailpipes that capture CO2 would make a dent in humans' contributions to greenhouse gas emissions. Learn about tailpipes that capture CO2 and if they exist. See more »

Why is there a bulge in the exhaust pipe of my dirt bike?

I have a dirt bike, and the exhaust pipe has this big bulge in it near the engine. What is the bulge for? See more »

How Mufflers Work

How Mufflers Work

Mufflers cancel out most of an engine’s noise. Find out how mufflers cancel sound waves, why engines are so loud, and look inside a muffler to learn about backpressure. See more »

How Catalytic Converters Work

How Catalytic Converters Work

Catalytic converters are one of the most important parts of a car's emissions control system. Learn about catalytic converters and catalytic converter laws. See more »

How do I know if my catalytic converter has failed?

How do I know if my catalytic converter has failed?

Catalytic converter failure can be hard to diagnose. Learn several possible causes for catalytic converter failure on this page. See more »