Air pollution is caused by solid, liquid and gases in the air also known as aerosols. This particles and gases can come from many sources, including vehicles, power plants, trash burning, agriculture, etc. Air pollution can be harmful to the planet and to human health. It can contribute to global warming, and one study found that emissions from fossil fuel combustion combustion contribute to 65 percentage of additional mortality due to exposure. Air pollution can also cause acid rain, ozone depletion, and damage to ecosystems and wildlife.