This document discusses the negative impacts of carbon-based fuels on human health and the environment. It notes that vehicle emissions contain pollutants like carbon monoxide, nitrogen oxides, and particulate matter which can cause cancer, respiratory illnesses, and other health problems. These emissions also harm the environment by affecting plants, soil, water and air quality. The document then provides a brief history of laws passed in the United States to regulate vehicle emissions and encourage the development of alternative fuels to address these issues.