A nebulizer configured to atomize a liquid medication for inhalation by a user, the nebulizer comprising: a jar defining a reservoir configured to hold the liquid medication, the jar defining a compressed gas passage configured to receive a flow of compressed gas; the compressed gas passage terminating in a jet orifice defined by the jar through which the liquid medication and the compressed gas are discharged through to form an aerosol flow having the liquid medication entrained in the compressed gas; a cap connected to the jar to define an inner chamber inside the nebulizer, the cap comprising: an entrainment port configured to provide an inlet for a flow of ambient room air, the entrainment port further configured to provide an inhalation pathway for inhalation through the entrainment port and an exhalation pathway for exhalation through the entrainment port; an entrainment chimney having a first opening in fluid communication with the entrainment port and a second opening in fluid communication with the inner chamber, the entrainment port and entrainment chimney together defining an entrainment pathway for the ambient room air; a deflector base spaced below the second opening of the entrainment chimney by a predetermined distance to define at least one entrainment vent configured to provide a flow of the ambient room air into the inner chamber for enhancing nebulization speed of the nebulizer, such that the at least one entrainment vent is configured to entrain the ambient room air into the aerosol flow to form an ambient air-entrained aerosol spray for inhalation by the user, further comprising a plurality of support fins (48A. 48B, 48C) connecting the deflector base to the entrainment chimney, wherein each of the at least one entrainment vent is provided between adjacent support fins (48A. 48B, 48C). a jar defining a reservoir configured to hold the liquid medication, the jar defining a compressed gas passage configured to receive a flow of compressed gas; the compressed gas passage terminating in a jet orifice defined by the jar through which the liquid medication and the compressed gas are discharged through to form an aerosol flow having the liquid medication entrained in the compressed gas; a cap connected to the jar to define an inner chamber inside the nebulizer, the cap comprising: an entrainment port configured to provide an inlet for a flow of ambient room air, the entrainment port further configured to provide an inhalation pathway for inhalation through the entrainment port and an exhalation pathway for exhalation through the entrainment port; an entrainment chimney having a first opening in fluid communication with the entrainment port and a second opening in fluid communication with the inner chamber, the entrainment port and entrainment chimney together defining an entrainment pathway for the ambient room air; a deflector base spaced below the second opening of the entrainment chimney by a predetermined distance to define at least one entrainment vent configured to provide a flow of the ambient room air into the inner chamber for enhancing nebulization speed of the nebulizer, such that the at least one entrainment vent is configured to entrain the ambient room air into the aerosol flow to form an ambient air-entrained aerosol spray for inhalation by the user, an entrainment port configured to provide an inlet for a flow of ambient room air, the entrainment port further configured to provide an inhalation pathway for inhalation through the entrainment port and an exhalation pathway for exhalation through the entrainment port; an entrainment chimney having a first opening in fluid communication with the entrainment port and a second opening in fluid communication with the inner chamber, the entrainment port and entrainment chimney together defining an entrainment pathway for the ambient room air; a deflector base spaced below the second opening of the entrainment chimney by a predetermined distance to define at least one entrainment vent configured to provide a flow of the ambient room air into the inner chamber for enhancing nebulization speed of the nebulizer, such that the at least one entrainment vent is configured to entrain the ambient room air into the aerosol flow to form an ambient air-entrained aerosol spray for inhalation by the user, further comprising a plurality of support fins (48A. 48B, 48C) connecting the deflector base to the entrainment chimney, wherein each of the at least one entrainment vent is provided between adjacent support fins (48A. 48B, 48C).