Generation of high concentrations of respirable solid-phase aerosols from viscous fluids

Abstract

High outputs of respirable solid-phase aerosols were generated from viscous solutions or suspensions of low and high molecular weight polyvinylprrolidone (PVP) solutions, 10% (w/v) albumin and, gamma-globulin solutions as well as 10.3% (w/v) surfactant suspensions. A central fluid flow was aerosolized by coaxial converging compressed air. The water was evaporated from the droplets using warm dilution air and infrared radiation. The resulting aerosol particles were concentrated using a virtual impactor. The aerosols were generated at fluid flow rates between 1 and 3 ml/min and delivered at a flow rate of 44 l/min as 2.6 – 3.6 μm MMAD aerosols with geometric standard deviations between 1.5 and 2. Increases in viscosity over the range of 4 to 39 cSt caused a modest increase in MMAD. Increases in aerosol exit orifice diameter was associated with a decrease in aerosol diameter. Increases in compressed air pressure caused a decrease in aerosol diameter. Increases in fluid flow rate resulted modest increases in MMAD together with proportional increases in output mass. Aerosolizing 10% 8 kDa PVP at 3 ml/min resulted in the delivery of 193 mg/min of PVP at 64% efficiency enabling 1.2 g to be collected in 7 min. Aerosolizing 10.3% surfactant suspensions at 3 ml/min resulted in the delivery of up to 163 mg/min with 59% efficiency. The surface tension of the surfactant was not changed by these processes. SEM showed dimpled particles of PVP, albumin and gamma globulin indicating that their aerodynamic diameter was less than their morphometric diameter.

Investigation of aerosol droplets diameter generated in aerosol jet printing

“…Therefore, the separation of viscous ink into droplets was hindered. Similar results were obtained by Heng et al [44] who generated solid phase aerosols from viscous solutions or suspensions and found that the increase in velocity in the range from 4 cSt to 39 cSt caused a modest increase in the median aerodynamic diameter. On the other hand, low viscosities usually lead to satellite formation.…”

Humidifier disinfectant, sodium dichloroisocyanurate (NaDCC): assessment of respiratory effects to protect workers’ health

“…The average concentration in the chamber measured during the exposure period of the test substance was < 20%, which satisfies the conditions for aerosol generation in OECD TG412 17 . This was thought to be due to the increase in compressed air pressure to increase the concentration of the test substance in the chamber when the test substance was generated 18 .…”