Dismantling myths on the airborne transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)

Abstract

stimulate revision of the science in the light of current evidence. Six 'myths' are presented, explained and ultimately refuted on the basis of recently published papers and expert opinion from previous work related to similar viruses. There is little doubt that SARS-CoV-2 is transmitted via a range of airborne particle sizes subject to all the usual ventilation parameters and human behaviour. Experts from specialties encompassing aerosol studies, ventilation, engineering, physics, virology and clinical medicine have joined together to produce this review to consolidate the evidence for airborne transmission mechanisms, and offer justification for modern strategies for prevention and control of COVID-19 in health care and the community.

Exposure to SARS-CoV-2 in Aerosolized Wastewater: Toilet Flushing, Wastewater Treatment, and Sprinkler Irrigation

“…Toilets are generally indoor, having limited potential for aerosolized virus dilution as compared with the outdoor settings (wastewater treatment facilities and sprinkler irrigation systems). It has also been recommended to ensure sufficient and effective ventilation, possibly enhanced by air filtration and disinfection [22]. In addition, modification in toilet designs should also be considered [19].…”

Covid-19 has redefined airborne transmission

“…Essentially, if you can inhale particles—regardless of their size or name—you are breathing in aerosols. Although this can happen at long range, it is more likely when close to someone, as the aerosols between two people are much more concentrated at short range, rather like being close to someone who is smoking 4…”

Drying of virus-containing aerosol particles: Modelling effects of droplet origin and composition

“…Aerosol transmission is most likely in enclosed spaces such as schools, public buildings and transportation 10,11 . Aerosols can transmit viruses from person to person with transiently inadequate social distancing 4 , but they can also build up, over minutes to hours, throughout the air in an enclosed space so that the risk of infection depends on the duration of emission and exposure, not on distancing 12 . In these circumstances the risk depends on Wells-Riley dynamics 13 and is reduced by ventilation with fresh or filtered air and by anything that decreases the viable lifetime of the virus 11,12 .…”

“…Aerosols are conventionally defined as droplets or particles less than 5-10 μm in diameter that, according to Stokes’ Law, remain suspended in still air for minutes or longer 2 . It has been argued 3,4 that the size range should be extended to 50-100 μm because turbulence, either in a cough jet 5 or due to draughts 6 or convection 7 , keeps larger particles airborne for longer than is predicted by Stokes’ Law.…”