A wind turbine tower includes a door access opening in a down tower area of the tower. A hinged door panel covers the door access opening, with a ventilation opening defined through the door panel. A multi-sided intake structure, such as a box-like structure, is connected to an exterior of the door panel over the first ventilation opening. The intake structure extends transversely from the door panel and includes a top side, a bottom side, and at least two vertical sides extending between the top side and the bottom side. The vertical sides are open to air flow therethrough. The top and bottom sides may also be open to air flow therethrough. Air from multiple directions is drawn into an interior of the wind turbine tower through the intake structure and ventilation opening. A filtering system with first and second stage filters may be incorporated with any of the intake structures.