Abstract: Sulfur oxides are removed from a gas containing same by contacting the gas with a system including ammonium, potassium, and/or sodium salts in a solid phase and ammonium, sodium, and/or potassium hydrogen sulfate in a liquid phase. The sulfur oxides react with the solid phase to form a hydrogen sulfate in a liquid phase. The hydrogen sulfate is regenerated and returned to the reaction zone as a sulfate. Sulfuric acid may be produced as a byproduct. Ammonia injection into the gas stream which optionally contains nitrogen oxides, converts the nitrogen oxides into nitrogen. The excess ammonia reacts with the sulfur oxides to precipitates in the sulfur oxides reaction zone.