According to researchers from Quebec, Illinois, and Texas, to prevent the spread of COVID-19 indoors, the two meters physical distancing guideline is not enough without masks.
The findings of the study were published in the journal 'Building and Environment'.
Wearing a mask indoors can reduce the contamination range of airborne particles by about 67 percent.
"Mask mandates and good ventilation are critically important to curb the spread of more contagious strains of COVID-19, especially during the flu season and winter months as more people socialize indoors," said Saad Akhtar, a former doctoral student under the supervision of Professor Agus Sasmito at McGill University.
While most public health guidelines recommend physical distancing of two metres for people from different households, the researchers say distancing alone is not enough to prevent the spread of COVID-19.
In this study, researchers found that when people are unmasked, more than 70 percent of airborne particles pass the two meters threshold within 30 seconds. By contrast, less than 1 percent of particles cross the two-meter mark if masks are worn.
Building on models used by scientists to study the flow of liquids and gasses, the team from McGill University, Universite de Sherbrooke, Texas A&M University, and Northern Illinois University, developed a computer program to accurately simulate coughing dynamics in indoor spaces.
While ventilation, a person's posture, and mask-wearing impacted the spread of the bio-contaminants significantly, the impact of age and gender was marginal, the researchers found.
Coughing is one of the main sources of the spread of airborne viruses from symptomatic individuals.
"This study advances the understanding of how infectious particles can spread from a source to its surroundings and can help policymakers and governments make informed decisions about guidelines for masks and distancing in indoor settings," Akhtar concluded.