Method for handling outlet air in a pneumatic waste-conveying system, in which the outlet air is at least partly the conveying air to be used in waste conveying. A method, graphical user interface, computer program product and use is also provided. In this case, the metals or alloys are the carriers of proton HProton H also can be provided from hydrogen gas by the use of catalysts located on the surface of carriers. The DAC receives a digital input signal and converts it into an analog output signal according to the first sampling signal.