Abstract: A method for cleaning process gases is provided, in which a sorbent is supplied to the process gases for reaction with gaseous pollutants that are present therein, thereby forming particulate reaction products which are separated in a subsequent particulate separator, and in which the moisture content and temperature of the cleaned process gases are measured to determine the relative humidity of the process gases and the concentration of at least one of the gaseous pollutants in the cleaned process gases is measured, wherein the relative humidity of the process gases is increased from a substantially constant basic level (BL) to an increased level (IL) and the amount of sorbent supplied to the process gases is increased when the concentration of at least one gaseous pollutant in the cleaned process gases exceeds an upper limit value (UL), and wherein the relative humidity is decreased back to said basic level, after a period of time and/or when the concentration of at least one gaseous pollutant in the cleane