An air handling system comprising a top cover (1), a base (5) and at least one air handling device (2, 3, 4) arranged between the top cover (1) and the base (5). At least one air inlet (191) is arranged on the bottom surface of the top cover (1), an air inlet is arranged on a side wall of the air handling device (2, 3, 4) adjacent to the base (5), and at least one air outlet (432) is arranged on the top of the air handling device (2, 3, 4).