Kyoto Protocol European Union-15, made up of 15 states at the time of the Kyoto negotiations) commit themselves to binding targets for GHG emissions. The targets apply to the four greenhouse gases carbon dioxide (), methane (), nitrous oxide (), sulphur hexafluoride (), and two groups of gases, hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs). The six GHG are translated into CO equivalents in determining reductions in emissions. These reduction targets are in addition to the industrial gases, chlorofluorocarbons, or CFCs, which are dealt with under the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer. Under the Protocol, only the Annex I
Sulfur dioxide and 2002. This improvement resulted in part from flue-gas desulfurization, a technology that enables SO to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite: Aerobic oxidation of the CaSO gives CaSO, anhydrite. Most gypsum sold in Europe comes from flue-gas desulfurization. Sulfur can be removed from coal during burning by using limestone as a bed material in fluidized bed combustion. Sulfur can also be removed from fuels before burning, preventing formation of SO when the fuel is burnt. The Claus process is used in