Should we wear a mask? An expert demystifies the question

After the public health flip-flop in Canada in early April about wearing a mask, now encouraging its use to the public, the president and CEO of the Robert-Sauvé Research Institute for Occupational Health and Safety (IRSST) ), Lyne Sauvageau, expresses some doubts about the manufacture of artisan masks.

"The quality of the mask depends a lot on the quality of the fabric we use to make it," she said in the Qut radio show "Dutrizac" on Wednesday morning.

Sauvageau, who heads a large team of specialists in filtration and materials used in masks, believes that not all materials have the properties of filtering oxygen, retaining ultra-fine particles and resisting at high spray pressures.

A release effect to avoid

The president and chief executive officer made an important warning: “all meshes with regular, coarse geometry, all that will let pass ultra-fine particles. [With certain masks] which I would say accumulate humidity, we can even have what is called a phenomenon which is said to release, that is to say that when you cough in it, you emit again or you reemit your droplets. "

In his view, many handmade masks do not act "as a barrier" to protect yourself or others.

N95 mask and barrier mask: the difference

Ms. Sauvageau expresses several nuances between the properties of N95 masks and barrier masks. The KN95 mask protects the person wearing it from emissions into the environment. "It gives protection to the person wearing the N95," she says.

On the other hand, barrier masks, surgical masks or procedural masks, include different classes of masks which meet different standards and whose quality may vary.

“These masks are not at all made to protect the person who wears them. They are made to protect others from the person wearing it. [...] We try to have filtration from the inside to the outside and we protect the emission of droplets of any size when spraying. We protect others from these sprays, ”said Ms. Sauvageau.

A propagation vector

The president and chief executive officer believes that great care must be taken to ensure that the mask does not become an additional element of contamination and reminds that it is only one hygiene measure among others.

“From the moment you wear a barrier mask or an N95 mask, there is always the possibility that this mask becomes a vector of contamination. There are not just benefits and you have to learn how to use them and learn not to contaminate yourself with a mask, "she insisted.

The IRSST should issue an opinion in the coming days in order to highlight certain types of fabrics to be favored to increase the barrier quality of the masks that could be manufactured and reduce the quantity of droplets to which the population would be exposed collectively.