Article discusses how ammonium sulfate (AS) is of interest as an additive in stationary combustion plants for the simultaneous control of NOx (through selective noncatalytic reduction, SNCR) and deposition and corrosion (through sulfation of alkali chlorides). The results indicated that sulfur from ammonium sulfate is mainly released as SO3, even though SO2 is detected in increasing concentrations at temperatures above 1000 °C. This is the accepted manuscript version of the published article.