A nebulizer for efficiently and reliably delivering aerosolized fluid to an inhaling patient is disclosed. The nebulizer includes a fluid channel air inlet and fluid channel air inlet valve responsive to either a manual force external of the nebulizer, or a patient's breathing, to begin the nebulization process. Also provided is a method of providing nebulization including the steps of moving a fluid channel air inlet valve against a fluid channel air inlet so that a negative pressure may build up over the fluid in the fluid channel to draw fluid from the fluid reservoir and begin nebulization during inhalation.