Side brooms brush material inwards in front of the sweeping nozzle(s). Vacuum, created inside the hopper by a large fan, pulls the material from the nozzle up into the hopper where large debris falls to the bottom. The air is then drawn through a large folded screen that causes any remaining dust and light debris to fall to the bottom of the hopper as well. The clean air then enters the fan inlet and continues up into the exhaust diffuser where the air is filtered one more time before being released back into the atmosphere.