The present invention is directed generally to a nebulizer for the formation of micro-droplets from liquid medicaments for respiratory patient treatment, and more specifically, to a baffled nebulizer wherein a static baffle used to form an atomized medicament is proximal to a shied which responds to patient respiration force to oscillate from an aerosol flow occluding position to an aerosol flow open position. During inhalation, the shield moves into a first registration format to allow passage of the atomized medicament (nebula) to the patient. During exhalation/non-use, a biasing pressure maintains said shield in a second registration format such that the nebula is retarded from passing to the patient and is coalesced into macro-droplets which return to a supply reservoir for re-atomization. The present nebulizer design is particularly adaptable for controlling atomization in response to patient respiratory forces exceeding a defined threshold; allowing for opportunity to control inhalation airflow and enhanced therapy regimes.