Original sentence: However, the ethanol program was not perfect and brought a host of environmental and social problems of its own.The improvement in air quality in big cities in the 1980s, following the widespread use of ethanol as car fuel, was widely evident; as was the degradation that followed the partial return to gasoline in the 1990s
Edited sentence: Ethanol is disastrous for the environment.Ethanol is worse for the environment than gasoline.Even though it is cheaper it requires more burning and more production of carbon dioxide than gasoline does.The energy that goes into producing one gallon of ethanol can feed one person for a whole year.The ethanol program was not at all perfect and brought a host of environmental and social problems of its own