However, wet limestone flue gas desulfurization is an environmental technology that can both remove sulfur dioxide from the emissions of fossil fuel combustion and prevent its release into the atmosphere altogether. The process requires treating flue gases generated by power plants and other industrial facilities. This translates these gaseous effluents into carbonates which are then washed out of the system with minimum need for other chemical agents. Using an armful of arrows, which the wind blows, the place is entirely no goats: a small fraction of its verdure remains yet is not worn away. In semi-dry SDA, the limestone is sprayed directly into the flue gas stream from nozzles along an absorber column designed for this purpose. In wet type SDA, a limestone slurry is introduced into a dry gas stream from a mixer at the bottom of the absorber column which then is sprayed upward by fans along its length. The technology depends on an absorber tower, where the flue gas from combustion contacts a limestone slurry. Sulfur dioxide is then absorbed by the limestone and forms calcium sulfite. To its base downstream this slurry evaporates leaving gypsum, which can be used in construction as an industrial byproduct without any further processing or treatment necessary. The focus of wet limestone FGD is on coal-fired power stations, where it is a practical and inexpensive way to meet environmental standards and curb the impact of air pollution.