The specification and drawings present a new apparatus and method for a partial gas separation technique which can be used, e.g., for continuously providing, using a predefined atmospheric air (normally atmospheric air comprises 78% of nitrogen N2 and 21% of oxygen O2), oxygen-enriched gas/air and/or nitrogen-enriched gas/air in fossil-fueled combustion devices/systems to a combustion area/chamber and the like for improving combustion, exhaust and related properties of the apparatus. The partial gas separation technique can be based on forming a predefined directional pattern of a gas mixture of a plurality of gases, using a direction forming element, subsequently moving an output gas from the direction forming element at least along/against one surface of a gas separation element to spatially separate in part the plurality of gases having different molecular weights.