Most cars have a typical combustion engine that burns fuel for energy, which results in the production of a wide variety of harmful chemicals like carbon dioxide, volatile organic compounds and particulate matter. Additionally, cars require several liquids to run that are toxic to people, animals and plants.
Carbon dioxide is the most common greenhouse gas that humans produce; the EPA estimates that carbon dioxide makes up 82 percent of all human greenhouse gas production. It is responsible for trapping heat within the atmosphere and contributes to climate change issues.
Car engines also produce a wide array of particles that are directly harmful to human and animal health. Hydrocarbons and particulate matter can cause breathing difficulties and long-term diseases. Many hydrocarbons are known to be carcinogens, which means they cause cancer.
In cities with high road traffic, smog is often an issue in the summer. Smog is caused by sunlight interacting with ozone and carbon monoxide in warm conditions, which is why smog is worst in the summer. Ozone and carbon monoxide are both produced in substantial amounts by most cars.
Vehicle fluids like antifreeze, motor oil windshield wiper fluid are dangerous for both people and animals. When these fluids leak, they can drain into water supplies or poison an animal that ingests them.