Just How Far Can Trading Of Emissions Be Extended?

Focuses on the U.S. President George W. Bush's administration's initiative to reduce pollution from power plants. Plans to replace air quality controls and apply emissions trading to other pollutants; Warnings of environmentalists and economists that the plan threatens to intensify pollution in certain so-called hot spots; Bush's failure to focus on greenhouse gases like carbon dioxide; History of emissions trading, which was set up by Congress; Implications of the plan; Views of experts.