A portable cleaning apparatus comprises a base module for movement along a surface and a plenum. The base module comprises a base housing enclosing a fan for moving air through the housing from the interior of the housing to the exterior of the housing through an exhaust outlet in the housing. The plenum fluidly communicates at one end with the exhaust outlet and at another end with at least one plenum outlet opening adjacent the surface to direct air exhausted from the housing interior along the surface.