A sulfur dioxide (SO2) Cap and Trade program has proven an effective control strategy to lower SO2 emissions. It provides ... was established under the 1990 Clean Air Act Amendments and requires major emission reductions of SO2 and nitrogen oxides (NOx ... A sulfur dioxide (SO2) Cap and Trade program has proven an effective control strategy to lower SO2 emissions. It provides ... Environmental Protection Agency announced today that power plants across the country decreased emissions of sulfur dioxide (SO2 ...