The SARS-CoV-2 global pandemic has highlighted the risk of nosocomial infections of airborne viruses to patient populations around the world. Increased use of mechanical ventilation and portable air cleaners (PACs) have been suggested as methods to mitigate this risk, but the introduction of new air flows to indoor areas can have complex and potentially unforeseen consequences. We used particle counters to investigate the effect of using built-in mechanical ventilation and/or PACs in a typical hospital outpatients’ clinic upon the spread of aerosols produced by an aerosol generator. A variety of scenarios was investigated, examining particle movement to a neighboring room, throughout the whole clinic, and from one room to another at the far side of the clinic. Whilst both built-in ventilation and PACs may reduce particle migration in some scenarios by up to 96%, use of the same PACs may lead to unexpectedly increased aerosol migration of 29% between neighboring rooms, and use of built-in supply ventilation may increase aerosol migration across the clinic by up to 5.5 times. These increases are most likely due to the introduction of air flows from the outlets of these devices, providing aerosols with enough momentum to traverse the distance between relatively remote locations or creating recirculation regions that pull aerosols out of one room and push them into another.
Accordingly, in order to effectively deploy these useful mitigations to their full potential and not simply displace the risk of nosocomial infection, careful consideration of placement and resultant air flow dynamics is required.
https://www.tandfonline.com/doi/full/10.1080/02786826.2024.2446587
2 Medical News 