Efficacy of the PlasmaShield®, a Non-Thermal, Plasma-Based Air Purification Device, in Removing Airborne Microorganisms

Abstract

Airborne microorganisms play a significant role in the transmission of infectious diseases. As such, improving indoor microbial air quality can enhance infection control in numerous settings. This study examined the efficacy of the PlasmaShield® air purification device to remove airborne microorganisms under laboratory conditions. Pure cultures of model microorganisms at varying concentrations were aerosolized using a 1-jet Collison nebulizer through stainless-steel removable piping prior to reaching the PlasmaShield® device. The surviving microorganisms were captured using the Staplex® MBS-6 Six Stage Microbial Air Sampler and enumerated via culture on agar plates. The positive-hole-corrected colony/plaque-forming units were compared with the negative control (microorganisms aerosolized through an empty PlasmaShield® casing). The PlasmaShield® statistically significantly (p < 0.05) reduced airborne Escherichia coli, Staphylococcus epidermidis, Bacteriophage MS2 and Cladosporium sp. compared with the negative control. The maximum removal achieved was estimated to be 4 × log10E. coli (99.99% removal), 4 × log10S. epidermidis (99.97% removal), 7 × log10 MS2 (99.99998% removal) and 5 × log10Cladosporium sp. (99.999% removal). Scanning electron microscope images of the surviving microorganisms showed that the PlasmaShield® damaged the cell membrane of these model microorganisms. This study provides proof-of-concept evidence to support the use of this technology to improve indoor microbial air quality.

Diagnostics of Air Purification Plasma Device by Spatially Resolved Emission Spectroscopy

“…In addition, by adding an electric charge to passing particles, the PlasmaShield ® device (PlasmaShield®, MD250, Keswick, SA, Australia) is able to collect the fine particles in the air flow and chemically decompose VOCs into harmless compounds. It has recently been evaluated for its ability to inactivate airborne microbes and remove VOCs and related compounds [27][28][29]. It is therefore important to investigate the plasma characteristics generated by PlasmaShield ® as a benchmark to correlate the generated plasma field and its performance.…”

Relative Health Risk Reduction from an Advanced Multi-modal Air Purification System: Evaluation in a Post-surgical Healthcare Setting

“…PlasmaShield® is a medical grade multi-modal air purifier fitted to a new or existing HVAC system. Laboratory tests demonstrate effective particle removal and the mitigation of microbial contamination via multiple modes of action (electron beam irradiation, electric field electroporation and final filtration) [24,25].…”