A PDC drill bit for use in downhole air drilling includes a body with a face for engaging a bottom of a hole being drilled and a gauge for engaging a side of the hole being drilled. The face includes a cone, a nose outward of the cone, a shoulder outward of the nose. The bit further includes channels formed in the face of the bit that extend from within the cone to the gauge. The channels define a plurality of blades separated by the channels. Each of the plurality of blades has a leading edge with PDC cutters mounted thereon. One or more of the channels are defined by two side walls and a bottom wall and has a length, width and depth. The width or depth remains substantially constant from a first point on its length within the cone to a second point within the shoulder.