A centrifugal blower (122, 122a), comprising a centrifugal fan (34, 34a, 34c) comprising: a hub adapted for rotation about a central axis; a first plurality of blades arranged about the central axis, wherein each of the blades defines: a leading edge; a trailing edge; a first side edge extending between the leading edge and the trailing edge, the first side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; a second side edge extending between the leading edge and the trailing edge, a portion of the second side edge integral with at least a portion of the hub, the second side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; an inlet radius defined as an outermost radius of the blade leading edge; an intermediate radius defined as an innermost radius of a shroud; the shroud being integral with at least a portion of the first side edges of the first plurality of blades; the blades having a curvature in a first plane, the first plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than a hub radius and less than the inlet radius; and the blades having no curvature in a second plane, the second plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than the intermediate radius; characterised in that the hub, the first plurality of blades, and the shroud are formed as one piece. a hub adapted for rotation about a central axis; a first plurality of blades arranged about the central axis, wherein each of the blades defines: a leading edge; a trailing edge; a first side edge extending between the leading edge and the trailing edge, the first side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; a second side edge extending between the leading edge and the trailing edge, a portion of the second side edge integral with at least a portion of the hub, the second side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; an inlet radius defined as an outermost radius of the blade leading edge; an intermediate radius defined as an innermost radius of a shroud; the shroud being integral with at least a portion of the first side edges of the first plurality of blades; the blades having a curvature in a first plane, the first plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than a hub radius and less than the inlet radius; and the blades having no curvature in a second plane, the second plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than the intermediate radius; characterised in that the hub, the first plurality of blades, and the shroud are formed as one piece. a leading edge; a trailing edge; a first side edge extending between the leading edge and the trailing edge, the first side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; a second side edge extending between the leading edge and the trailing edge, a portion of the second side edge integral with at least a portion of the hub, the second side edge being swept from the leading edge in a direction axially away from the leading edge and radially outward toward the trailing edge; an inlet radius defined as an outermost radius of the blade leading edge; an intermediate radius defined as an innermost radius of a shroud; the shroud being integral with at least a portion of the first side edges of the first plurality of blades; the blades having a curvature in a first plane, the first plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than a hub radius and less than the inlet radius; and the blades having no curvature in a second plane, the second plane extending through the blade and tangent to a cylinder which extends through the blade and is centered along the central axis, the cylinder being of a radius greater than the intermediate radius; characterised in that the hub, the first plurality of blades, and the shroud are formed as one piece.