TORONTO – A two-metre physical distance guideline without wearing a mask may not be enough to prevent the spread of COVID-19 indoors, says a new joint study, however, the contamination limit of airborne particles from wearing a mask is almost can be reduced to 67. Percent.

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The study, published in the December volume of the journal building and environment, was conducted by researchers from McGill University, Université de Sherbrooke, Texas A&M University and Northern Illinois University. The research was based on models that examined the flow of liquids and gases in indoor spaces using a computer program that accurately simulated cough dynamics.

Study author Saad Akhtar said in a release, “Mask mandatory and good ventilation are critically important to prevent the spread of more infectious strains of COVID-19, especially during flu season and the winter months, because More people socialize indoors.”

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Coughing is one of the main sources of transmission of the airborne virus from symptomatic individuals, and currently, most public health guidelines recommend a distance of two meters for physical distance between people who are from the same household to address it. are not.

However, the study found that when people are masked, more than 70 percent of airborne particles cross the two-meter threshold within 30 seconds. By comparison, less than one percent of particles cross the two-metre mark if a mask is worn.

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Cough simulations run by the study found that particles can reach distances of five meters or more if the person is without a mask and relies on ventilation and air conditioning.

The effect of wearing a mask indoors on the spread of particles over 30-second intervals can be seen here in a cough simulation run by the joint study. (McGill University / Building and Environment Journal)

The study found that ventilation, a person’s posture and wearing a mask had a significant effect on the spread of particulates, but age and gender had only minor effects.

Akhtar said, “This study advances the understanding of how infectious particles can spread from a source to its surroundings and helps policymakers and governments make informed decisions about mask guidelines and distancing in indoor settings. can do.”