Abstract: Described is a gas mixer preferentially employed for mixing at least two gas flows. The gas mixer comprises a first filter adapted to have a first gas flow directed therethrough from a first surface to a second surface thereof. A second gas flow is directed along the second surface of the filter so as to entrain the first gas exiting therefrom. The resulting gas mixture is subsequently caused to pass through a second filter and, if need be, through one or more additional filters.