The concentrations of fugitive aerosols produced in vivo by various nebulizers and interfaces, as well as the mitigation of aerosol dispersion into the environment using multiple commercially available devices, were unknown. About 9 healthy volunteers were given 3 mL saline with a mouthpiece, a mouthpiece with an exhalation filter, an aerosol mask with open ports for small-volume nebulizer (SVN) and a valved face mask for vibrating mesh nebulizer (VMN), and a face mask with a scavenger (Exhale) in random order with an SVN or a VMN with a mouth 5 of the volunteers were given treatments with SVN and VMN in a random sequence utilizing a face tent scavenger (Vapotherm) and a mask with exhalation filter. Aerosol concentrations at sizes of 0.3–10.0 μm were measured at baseline, before, during, and after each treatment in an ICU room with 2 particle counters positioned 1 and 3 ft from patients. Fugitive aerosol concentrations were higher with SVN than with VMN and with a face mask than with a mouthpiece. Aerosol concentrations of 0.3–1.0 μm for VMN and 0.3–3.0 μm for SVN were lowered when an exhalation filter was added to a mouthpiece (all P<.05). For SVN (all P<.05), an Exhale scavenger over the mask lowered 0.5–3.0 m sized particle concentrations, but not for VMN. Regardless of the nebulizer type, the Vapotherm scavenger and filter face mask decreased fugitive aerosol concentrations. SVN produced more fugitive aerosol concentrations than VMN, while face masks produced more aerosol concentrations than mouthpieces. Both SVN and VMN aerosol concentrations were lowered by using an expiration filter in the mouthpiece or a scavenger in the face mask. The Vapotherm scavenger and filter face mask was as effective as a mouthpiece with an exhalation filter to reduce fugitive aerosols. The study offered recommendations for minimizing nebulizer fugitive aerosol emissions in clinical practice.