Investigation of the quantity of exhaled aerosols released into the environment during jet nebulization

This study was designed to determine the amount of exhaled aerosol that is released into the environment when a patient undergoes aerosol therapy. The emitted aerosol concentration was measured with two Aerodynamic Particle Sizers (APS) at distances from the source of 0.8 m and 2.2 m respectively. Two simulated patients (adult and paediatric) were used in conjunction with a commonly used venturi type, jet nebuliser to determine the extent of secondary aerosol present during and after therapy. The patient interfaces assessed included facemask, mouthpiece without expiratory filter and mouthpiece with expiratory filter. Analysis of the data, indicates that the mouthpiece emitted greater amounts of aerosol to the environment than the facemask. Addition of a filter to the mouthpiece significantly reduced emissions when compared with no filter. This study shows that there is a substantial amount of aerosol released into the environment when a patient undergoes aerosol therapy during the standard of care and further, indicates that use of a expiratory filter can reduce, but not eliminate emissions.