According to researchers from Quebec, Illinois, and Texas, to prevent the spread of Covid-19 indoors, the two metres 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 per cent.

In this study, researchers found that when people are unmasked, more than 70 per cent of airborne particles pass the two metres threshold within 30 seconds. By contrast, less than 1 per cent of particles cross the two-metre mark if masks are worn.