COVID-19: Without masks, two meters distancing is not enough, research finds: Simulations track the spread of coughs and safe physical distancing indoors

Researchers from Texas, Illinois and Quebec found that masks are necessary to prevent COVID-19 spreading indoors. However, indoors wearing a mask can reduce the airborne particle contamination by around 67 percent.
"Mask mandates are critical to stop the spread of more contagious strains COVID-19, especially during flu season when more people socialize indoors," states Saad Akhtar (a former doctoral student) at McGill University.

Public health guidelines recommend a distance of at least two metres between people living in different homes. However, researchers claim that distancing is not sufficient to stop the spread of COVID-19. The researchers published a study in Building and Environment that found that more than 70% of airborne particles can pass the two-metre threshold within 30 seconds when people are not masking. Masks, however, only 1% of particles can cross the two-metre threshold.

Simulating coughing dynamics

Based on existing models that scientists use to study the flow and properties of liquids and gases, the McGill University, Universite de Sherbrooke and Texas A&M University teams developed a computer program that accurately simulates coughing in indoor spaces.

Researchers found that ventilation, posture and mask-wearing had a significant impact on the spread of bio-contaminants. However, age and gender had a marginal effect.

Coughing is a major source of transmission of airborne virus from symptomatic people. Akhtar says, "This study advances our understanding of infectious particles spreading from a source into its surroundings. It can help policymakers make informed decisions regarding guidelines for masks or distancing indoors."