Back to Normal: An Old Physics Route to Reduce SARS-CoV-2 Transmission in Indoor Spaces

Abstract

We advocate the widespread use of UV-C light as a short-term, easily deployable, and affordable way to limit virus spread in the current SARS-CoV-2 pandemic. Radical social distancing with the associated shutdown of schools, restaurants, sport clubs, workplaces, and traveling has been shown to be effective in reducing virus spread, but its economic and social costs are unsustainable in the medium term. Simple measures like frequent handwashing, facial masks, and other physical barriers are being commonly adopted to prevent virus transmission. However, their efficacy may be limited, particularly in shared indoor spaces, where, in addition to airborne transmission, elements with small surface areas such as elevator buttons, door handles, and handrails are frequently used and can also mediate transmission. We argue that additional measures are necessary to reduce virus transmission when people resume attending schools and jobs that require proximity or some degree of physical contact. Among the available alternatives, UV-C light satisfies the requirements of rapid, widespread, and economically viable deployment. Its implementation is only limited by current production capacities, an increase of which requires swift intervention by industry and authorities.

Occurrence, fates and potential treatment approaches for removal of viruses from wastewater: A review with emphasis on SARS-CoV-2

“…The coronaviruses also demonstrate a high sensitivity towards chlorine [ 99 ], thereby signifying the possible inactivation of SARS-CoV-2 by chlorination. Additionally, the ozone treatment has also been discussed to achieve efficient inactivation of viruses [ 100 ]. The higher levels of ozone, high temperature, and lower RH were reported to have a negative impact on the transmission of SARS-CoV-2.…”

Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19

“…It is noteworthy that, even in the absence of forced ventilation, there will generally be some mixing in an enclosed space: natural ventilation will lead to flows through windows or doors, and 19 , v = 0 0.63/h. We note that deactivation rates may be enhanced by ultraviolet radiation (UV-C) 40 , chemical disinfectants (e.g. 41 , or high-efficiency particulate air (HEPA) filtration 42 .…”

A Critical Review on Ultraviolet Disinfection Systems against COVID-19 Outbreak: Applicability, Validation, and Safety Considerations

“… 18 Tiny droplets (0.1–5 μm) are capable of dissolving with the aerosol, remaining airborne, and traveling hundreds of meters. 17 , 19 Intermediate size range (5–100 μm) droplets also shrink to tiny sizes due to evaporation, 17 and the peak concentration of droplets in bioaerosols are in two diameter ranges: 0.25–1.0 μm and 2.5–10 μm. 20 Factors such as air current, temperature, and humidity can also affect bioaerosol transmission rates.…”

“…Widespread use of UVC disinfectors is also advised to limit virus spread after reopening of public places. 17 However, limited understanding of the critical aspects of UV disinfection, not only among the majority of general public but also with some of the UV surface disinfection manufacturers, has led to inappropriate use of this promising technology. Dubious and nonscientific performance claims by some of the UV system designers and manufacturers are unfortunately widespread.…”