Externalities of automobiles are the impacts that cars have on the environment and people, beyond the people who own them or buy them. Cars have serious externalities that hurt the environment. They produce toxic chemicals like carbon dioxide and nitrogen oxides which are bad for the air. They also cause air pollution that can make it hard to breathe outside, and damage ecosystems like rivers and lakes that can't handle all the auto exhaust. Cars also use a lot of resources like oil and gas which can lead to energy shortages, and can be dangerous if spilled in large amounts. Cars also cause noise pollution which can disturb people's peace and quiet. Finally, cars add to global warming with all the exhaust they produce.