Turn up the lights, leave them on, and shine them all around - numerical simulations point the way to more efficient use of Far-UVC lights for the inactivation of airborne coronavirus

TY - JOUR

T1 - Turn up the lights, leave them on, and shine them all around - numerical simulations point the way to more efficient use of Far-UVC lights for the inactivation of airborne coronavirus

AU - Wood, Kenneth

AU - Wood, Andrew

AU - Peñaloza, Camilo

AU - Eadie, Ewan

N1 - Funding Information: The authors would like to thank Aaron Longbottom and Andrew Parker of Fluid Gravity Engineering for useful discussions about CFD and particle dissemination modeling. We acknowledge financial support from the University of St Andrews Restarting Research Funding Scheme␣(SARRF) which is funded through the Scottish Funding Council grant reference SFC/AN/08/020. Publisher Copyright: © 2021 American Society for Photobiology

PY - 2022/3/17

Y1 - 2022/3/17

N2 - It has been demonstrated in laboratory environments that ultraviolet-C (UVC) light is effective at inactivating airborne viruses. However, due to multiple parameters, it cannot be assumed that the air inside a room will be efficiently disinfected by commercial germicidal ultraviolet (GUV) systems. This research utilizes numerical simulations of airflow, viral spread, inactivation by UVC and removal by mechanical ventilation in a typical classroom. The viral load in the classroom is compared for conventional upper-room GUV and the emerging “Far-UVC.” In our simulated environment, GUV is shown to be effective in both well and poorly ventilated rooms, with greatest benefit in the latter. At current exposure limits, 18 commercial Far-UVC systems were as effective at reducing viral load as a single upper-room GUV. Improvements in Far-UVC irradiation distribution and recently proposed increases to exposure limits would dramatically increase the efficacy of Far-UVC devices. Modifications to current Far-UVC devices, which would improve their real-world efficacy, could be implemented now without requiring legislative change. The prospect of increased safety limits coupled with our suggested technological modifications could usher in a new era of safe and rapid whole room air disinfection in occupied indoor spaces.

AB - It has been demonstrated in laboratory environments that ultraviolet-C (UVC) light is effective at inactivating airborne viruses. However, due to multiple parameters, it cannot be assumed that the air inside a room will be efficiently disinfected by commercial germicidal ultraviolet (GUV) systems. This research utilizes numerical simulations of airflow, viral spread, inactivation by UVC and removal by mechanical ventilation in a typical classroom. The viral load in the classroom is compared for conventional upper-room GUV and the emerging “Far-UVC.” In our simulated environment, GUV is shown to be effective in both well and poorly ventilated rooms, with greatest benefit in the latter. At current exposure limits, 18 commercial Far-UVC systems were as effective at reducing viral load as a single upper-room GUV. Improvements in Far-UVC irradiation distribution and recently proposed increases to exposure limits would dramatically increase the efficacy of Far-UVC devices. Modifications to current Far-UVC devices, which would improve their real-world efficacy, could be implemented now without requiring legislative change. The prospect of increased safety limits coupled with our suggested technological modifications could usher in a new era of safe and rapid whole room air disinfection in occupied indoor spaces.

KW - Computational fluid dynamics

KW - Ultraviolet-C

UR - https://www.scopus.com/pages/publications/85117588490

U2 - 10.1111/php.13523

DO - 10.1111/php.13523

M3 - Article

C2 - 34599612

SN - 0031-8655

VL - 98

SP - 471

EP - 483

JO - Photochemistry and Photobiology

JF - Photochemistry and Photobiology

IS - 2

ER -