The danger of wearing old masks

Wearing masks has been highly recommended as a way of reducing transmission of coronavirus in communities. Masks simple barriers that help prevent the spread of respiratory droplets between people.

For instance, it is believed that N95 masks are designed to block 95 per cent of very small particles.

But a new study published this month in the journal Physics of Fluids has concluded that it is safer not to wear a mask than to put on an old one. Old masks are believed to have less than 30 per cent filtration efficiency hence wearing them can enhance the viral load on the respiratory tract.

Using a computational mask model, scientists were able to visualise how particles pass through the mask and deposit themselves onto the face, and enter the airways.

They discovered that the mask’s filtration efficacy is vital to protecting the wearer from inhaling potentially Covid-19 loaded particles.

Results showed that a new three-layer surgical mask could achieve 65 percent filtration efficacy while an old one could be as low as 25 percent. They concluded that wearing a mask with a 25 percent filtration efficacy may be worse than having none.

It was concluded that wearing a mask with a 25 per cent filtration efficacy may be worse than having none.