An air humidification system for large enclosed spaces, comprising at least one humidification line constituted by at least one humidification module comprising a box-like container with a water flow pipe inside which is functionally connected at its inlet to a water pump and at its outlet to a water discharge space. The pipe has, along its extension, a plurality of nozzles adapted to provide a water aerosol. The nozzles are open onto a first opening provided in the box-like container and are oriented toward the outside of the first opening. A cross-flow impeller is provided within the box-like container along a rotation axis which is parallel to the pipe and is suitable to aspirate air from a second opening of the box-like container and direct it toward the first opening.