ABSTRACT
Alternative fuels are used to supplement and replace petroleum-based gasoline, since burning fossil fuels releases carbon dioxide (CO2), damaging the environment and increasing global warming. Acid rain, smog, and air pollution are other environmental costs. The World Health Organization estimates over 5.5 million premature deaths worldwide are due to air pollution every year. Alternative fuels come from sources other than petroleum and can originate from natural gas, such as propane, methanol, or compressed natural gas, or from biomass materials, such as ethanol, soy diesel, or methanol. In some countries, gasohol—a mixture of gasoline and alcohol—and liquefied petroleum gas are also considered alternative fuels.
