Abstract: An aerosol preparation assembly includes an entrainment chamber defining an entrainment volume. The entrainment chamber includes a gas inlet port, an aerosol inlet port and an outlet port. The entrainment chamber is configured such that a velocity of a flow of a gas within the entrainment volume is less than a velocity of the flow of the gas within the gas inlet port. The entrainment chamber is configured such that at least a portion of inlet aerosol is entrained into the flow of the gas within the entrainment volume to produce an entrained aerosol flow at the outlet port. The particle selection chamber is configured to receive the entrained aerosol flow and produce an outlet aerosol flow. The particle selection chamber and nozzle are collectively configured such that a volumetric median diameter of the outlet aerosol flow is less than a volumetric median diameter of the inlet aerosol.