An aerosol generating device 101 comprising a vaporizer for heating an aerosol-forming substrate 115, a plurality of air flow vents 121, and at least one air outlet 123. The air flow vents 121 and the air outlet 123 are arranged to define an air flow route between the air flow vents and the air outlet. In each of the plurality of air flow vents 121 is an air inlet vent arranged to direct air towards the vicinity of the vaporizer in a direction across the surface of the vaporizer so as to manage particle size in the aerosol.