# Relative Health Risk Reduction from an Advanced Multi-Modal Air Purification System: Evaluation in a Post-Surgical Healthcare Setting

## TL;DR

A new air purification system significantly reduces airborne particles and infection risk in a hospital setting.

## Contribution

The study evaluates PlasmaShield® in a real-world healthcare setting, showing significant reductions in airborne particles and bioaerosols.

## Key findings

- PlasmaShield® reduced particle concentrations, especially virus-like submicron particles, in occupied spaces.
- Airborne bacteria and fungi in supply air were significantly reduced, with more modest effects in occupied spaces.
- The system provided an eight-fold improvement in clean air equivalent, suggesting a five-fold reduction in infection risk.

## Abstract

Advanced air treatment systems have the potential to reduce airborne infection risk, improve indoor air quality (IAQ) and reduce energy consumption, but few studies reported practical implementation and performance. PlasmaShield®, an advanced multi-modal HVAC-integrated system, was directly compared with a standard MERV-13 system in a post-surgical paediatric healthcare setting. The evaluation entailed monitoring of multi-size airborne particles, bioaerosols and key IAQ parameters. Measurements were taken for outside air, supply air and air in the occupied space for 3 days prior to, and after, the installation of the PlasmaShield system. Compared with the existing arrangement, very significant reductions in particle number concentrations were observed in the occupied space, especially with virus-like submicron particles. Significant reductions in airborne culturable bacteria and fungi were observed in the supply air, with more modest reductions in the occupied space. In the case of virus-like particles, there was an eight-fold improvement in equivalent clean air, suggesting a five-fold infection risk reduction for long-range exposure. The data suggest multiple benefits of airborne particle and bioaerosol reduction, with applications beyond healthcare. Long-term studies are recommended to confirm the combined IAQ, health and energy benefits.