Minimising exposure to respiratory droplets, ‘jet riders’ and aerosols in air-conditioned hospital rooms by a ‘Shield-and-Sink’ strategy

  title={Minimising exposure to respiratory droplets, ‘jet riders’ and aerosols in air-conditioned hospital rooms by a ‘Shield-and-Sink’ strategy},
  author={Patrick R. Hunziker},
  journal={BMJ Open},
  • P. Hunziker
  • Published 16 December 2020
  • Environmental Science
  • BMJ Open
Objectives In COVID-19, transfer of respiratory materials transmits disease and drives the pandemic but the interplay of droplet and aerosol physics, physiology and environment is not fully understood. To advance understanding of disease transmission mechanisms and to find novel exposure minimisation strategies, we studied cough-driven material transport modes and the efficacy of control strategies. Design Computer simulations and real-world experiments were used for integrating an intensive… 

Investigation of air change rate and aerosol behavior during an outbreak of COVID-19 in a geriatric care facility

Investigation of the air change rate using the tracer gas method in five areas where the risk of aerosol infection was assumed to be high for an outbreak of an infection among 59 people in a nursing home in Japan found that infectious aerosols could reach the day room in approximately one minute through the corridor.



Particle sizes of infectious aerosols: implications for infection control

  • K. Fennelly
  • Medicine, Environmental Science
    The Lancet Respiratory Medicine
  • 2020

On coughing and airborne droplet transmission to humans

It is found that human saliva-disease-carrier droplets may travel up to unexpected considerable distances depending on the wind speed, which implies that considering the environmental conditions, the 2 m social distance may not be sufficient.

Recognition of aerosol transmission of infectious agents: a commentary

This review considers the commonly used term of ‘aerosol transmission’ in the context of some infectious agents that are well-recognized to be transmissible via the airborne route, and discusses other agents, like influenza virus, where the potential for airborne transmission is much more dependent on various host, viral and environmental factors, and where its potential for aerosol transmission may be underestimated.

Measurements of Airborne Influenza Virus in Aerosol Particles from Human Coughs

The results show that coughing by influenza patients emits aerosol particles containing influenza virus and that much of the viral RNA is contained within particles in the respirable size range, supporting the idea that the airborne route may be a pathway for influenza transmission, especially in the immediate vicinity of an influenza patient.

Human Cough as a Two-Stage Jet and Its Role in Particle Transport

The results showed that the cough flow’s maximum penetration distance was in the range of a 50.6–85.5 opening diameter (D) under the authors' experimental conditions, and the real-cough and sinusoidal cases exhibited greater penetration ability than the pulsation cases under the same characteristic Reynolds number and normalized cough expired volume.

Consideration of the Aerosol Transmission for COVID‐19 and Public Health

The weight of the available evidence warrants immediate attention to address the significance of aerosols and implications for public health protection.

Airborne or Droplet Precautions for Health Workers Treating Coronavirus Disease 2019?

The weight of combined evidence supports airborne precautions for the occupational health and safety of health workers treating patients with COVID-19, and suggests that infections cannot neatly be separated into the dichotomy of droplet versus airborne transmission routes.

Transmission Potential of SARS-CoV-2 in Viral Shedding Observed at the University of Nebraska Medical Center

Air and surface samples collected during the initial isolation of 13 individuals confirmed positive with COVID-19 infection showed evidence of viral contamination, indicating that SARS-CoV-2 is shed to the environment as expired particles, during toileting, and through contact with fomites.

Evidence of airborne transmission of the severe acute respiratory syndrome virus.

Airborne spread of the virus appears to explain this large community outbreak of SARS in Hong Kong, and future efforts at prevention and control must take into consideration the potential for airborne spread of this virus.

Airflow Dynamics of Coughing in Healthy Human Volunteers by Shadowgraph Imaging: An Aid to Aerosol Infection Control

Real-time, non-invasive shadowgraph imaging was applied to obtain additional analyses of cough airflows produced by healthy volunteers and demonstrates that although this method rarely completely blocks the cough airflow, it decelerates, splits and redirects the airflow, eventually reducing its propagation.