Air pollution is an issue the United States has struggled with for many decades now. During the Industrial Revolution in the mid 19th century the United States created new sources of air pollution that eventually started to show in the 20th century. Today one of the leading causes of air pollution are systems of transportation like trains, cars, buses, and motorcycles..These mass produced vehicles create loads of negative emissions that cause an increase in the amounts of greenhouse gasses in the atmosphere. These vehicles use gas which when burned releases harmful substances like carbon monoxide, nitrogen oxides, and unburned hydrocarbons. Increased amounts of greenhouse gasses generate global warming which gives us another reason to begin working towards becoming more environmentally friendly. Air pollution is an issue that not only affects humans but the environment and even goes down to plants. It causes a domino effect starting from the air which later leads to affecting our health.