Using latex microspheres as model suspensions, the influence of suspension particle size (1, 4.5 and10 m) on the properties of aerosols produced using Pari LC Sprint (air-jet), Polygreen (ultrasonic),Aeroneb Pro (actively vibrating-mesh) and Omron MicroAir NE-U22 (passively vibrating-mesh) nebulisers was investigated. The performance of the Pari nebuliser was independent of latex spheres particle size. For both Polygreen and Aeroneb Pro nebulizers, total aerosol output increased when the size oflatex spheres increased, with highest fine particle fraction (FPF) values being recorded. However, fol-lowing nebulisation of 1 or 4.5 m suspensions with the Polygreen device, no particles were detected in the aerosols deposited in a two-stage impinger, suggesting that the aerosols generated from this deviceconsisted mainly of the continuous phase while the dispersed microspheres were excluded and remained in the nebuliser. The Omron nebuliser efficiently nebulised the 1 m latex spheres, with high output rate and no particle aggregation. However, this device functioned inefficiently when delivering 4.5 or 10 msuspensions, which was attributed to the mild vibrations of its mesh and/or the blockage of the meshapertures by the microspheres. The Aeroneb Pro fragmented latex spheres into smaller particles, butuncontrolled aggregation occurred upon nebulisation. This study has shown that the design of the neb-uliser influenced the aerosol properties using latex spheres as model suspensions. Moreover, for the recently marketed mesh nebulisers, the performance of the Aeroneb Pro device was less dependent onparticle size of the suspension compared with the Omron MicroAir nebuliser.
- Aerosol Latex sphereNebuliser Two-stage impinger Vibrating-mesh