Cabin pressurization system for agricultural machines with filtration system

Cabin air treatment apparatus for an agricultural machine, comprising at least an external air inlet, a filtration system, an HVAC system, and a cabin air supply outlet. The apparatus further comprises a hermetically closed box inside which the HVAC system is housed, the box having a levelling opening for placing the box into communication with a cabin of the agricultural machine to level a pressure inside the box with a pressure inside the cabin. The filtration system comprises a filter for effecting a filtration of at least one among dust, aerosols and vapours, arranged at an external air inlet formed on the box, and an air inlet duct arranged downstream of the filter and provided with a selecting valve having a first outlet connected to the HVAC system, and a second outlet connected to a fan of a condensation system, through a cleaning duct.