COVID-19: Study points to 3-pronged approach to mitigate airborne transmission

Improving ventilation in built spaces, building knowledge base to inform holistic decision-making are among recommendations published in a journal  

By Bhavya Khullar
Published: Monday 01 June 2020

Concerns over airborne transmission of the novel coronavirus SARS-CoV-2 and ways to deal with it have not received as much attention as they should have. This is particularly important as an effective vaccine for the novel coronavirus disease (COVID-19) is expected to take several months — or years. With lifting of the nationwide lockdown, a possibility of airborne transmission cannot be overlooked, according to field experts.

In a research paper published in journal City and Environment Interactions, authors Prashant Kumar and Lidia Morawska laid out a three-pronged approach using which airborne transmission of COVID-19 can be controlled.

While Kumar is a professor at the Global Centre for Clean Air Research, University of Surrey, United Kingdom; Morawska is a professor at the International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia.

According to the study, the three steps are:

  • Improving ventilation in built spaces
  • Protecting individuals from infection
  • Building a knowledge base to inform holistic decision-making in the best interests of the public and economy

The SARS-CoV-2 virus is tiny — less than 100  nanometres in size. Expiratory droplets containing the virus may become smaller and lighter to stay suspended in the air when the water evaporates.

These droplets increase the risk of infection, particularly if the air is stagnant, which is the case in many indoor environments at public places with insufficient and inefficient ventilation. Mechanical ventilation is common in many commercial and public buildings, but it may be ineffective, and may instead create a situation allowing the contaminated air to stay inside a built space.

At the same time, natural ventilation may not be a viable option due to the structural configurations of buildings and heating cooling, and energy constraints at many important places.

In such circumstances, it is required that ventilation strategies and filtering efficacy of installed systems are periodically reviewed to maximise the indoor-outdoor exchange of fresh air. Protecting individuals from infection is equally important.

“This can be achieved by use of personal protective equipment such as masks and face coverings, especially where the indoor infection risk is high. However, clear guidelines are needed on their short-term or situation-specific use,” said Kumar.

Creating a knowledge base for informed decision making requires government intervention.

“Scientific evidence to assess the intensity and probability of airborne transmission pathways as well as an understanding of transmission exposure at a personal level in microenvironments and indoor public spaces has to be conducted and documented,” said Lidia. It would also entail identifying individuals at high risk of infection and implementing measures targeted at specific places and for certain activities, she added.

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