The present invention relates to a blower comprising an electric motor having a shaft, said shaft defines a shaft axis； a housing having a housing inlet and a housing outlet between which is defined a flow path for gas； the housing outlet is structured to direct gas exiting the blower in a substantially axial first direction； the motor has a first side proximal said housing inlet, and a second side distal said housing inlet； a first impeller having a plurality of blades adapted to accelerate gas tangentially and to direct it radially outward and being attached to the shaft on the first side of the motor； a stationary portion including: a gas flow path defined between the motor external wall and a wall of the stationary portion, said flow path being of sufficient width to allow a flow of gas therethrough without introducing excessive pressure drop, said flow path directing gas to flow in a generally axial direction from the first side of the motor to the second side of the motor； a first stationary vane structure located downstream of the first impeller, the first stationary vane structure adapted to direct gas exiting the first impeller from flowing in a substantially tangential direction to flowing in both a radial and axial direction； and a shield constructed and arranged to provide a barrier between the first stationary vane structure and the blades of the first impeller to isolate leading edges of the first stationary vane structure from an impeller blade pressure pulse.
