An air supply device for the passenger cell of a motor vehicle includes a rotating element formed in an axial suction intake region of the air-conditioning blower and upstream of the air-conditioning blower. The rotating element covers the air inlet region such that all the sucked-in drops impinge onto the element. Arranged in front of the housing wall of the air supply device are drop interception elements which are fixed lamellae of low inclination or wedge structures with acute wedge angles. The drop interception elements are inclined so that the drops impinge at an acute angle. Active water and particle (pre)-separation is thereby ensured.