Finding correct information about mouth masks is not easy. Which type of mouth mask should I buy? What exactly do they protect against? Is a homemade mask enough? Are there any risks associated with using a mask? We want to give a clear answer to these questions here in this blog.

Today: the strange twist in advice on mouth masks. Why is it now suddenly recommended to wear a mouth mask?

Not so long ago, at the beginning of the pandemic in March, the use of mouth masks was explicitly discouraged for those who were not medical personnel or who did not show any symptoms of disease. Officially, that is still the advice of the World Health Organization (WHO) today.

What has changed then? Countries in control of the contamination curve have started to phase out the strictest lockdown measures. Where until recently only essential trips were allowed, we can now also take the car for relaxation. Where contact was limited to our own family, we can now go back to work, shop or visit a limited group of people. Although always under the condition that we strictly adhere to the social distance of 1.5M, wash hands regularly and sneeze in the elbow cavity.

So with the easing of the measures, the potential number of contacts that we have every day again increases. But not only the number of contacts increases, but also the chance that we get into a situation where it is impossible to keep the minimum distance of 1.5M.

The importance of that distance becomes clear when we look again at how the virus spreads. A person who carries the coronavirus sends thousands of tiny droplets into the air when coughing, sneezing, or speaking. A single cough can produce up to 3000 drops. Even just saying “stay healthy” we spray thousands of drops around, according to a recent study. Some of those drops will evaporate. The largest drops end up on surfaces in the immediate vicinity, while the smallest ones can linger in the air for quite some time. Hence the increased risk in smaller, closed spaces.

That is also the reason why it is mandatory today in many countries – including Belgium – to wear a mask on public transport. Other countries such as the Czech Republic, Slovakia, Morocco, Turkey and Germany go even further and oblige everyone who comes outside to wear a mask.

So the chance increases that as more people get out, it also becomes difficult to keep that 1.5M distance. And in order to reduce the risk of contamination in such a case, it is recommended today to wear mouth masks together. The mask largely blocks those tiny, often invisible, moisture drops that sneeze when speaking or coughing – as becomes clear in the video below from the same study. But the effect increases when two people at the shorter distance each wear a mask. In that case, the mask stops drops when leaving one person, while the drops that still escape the mask can be stopped by the mask of the other person. In a conversation between two people, they both have a direct advantage when wearing a mask.

However, we should not forget that the drops also fall on the surface all around. And that there is always a risk of contamination by moving your hand over such a surface and then touching your mouth, nose or eyes. Besides the social distance, hand washing remains the most important basic rule.

The masks we consideed here do not distinguish between types. Since any type – tightly fitting – mask will stop drops. The different types of masks, each with their own properties, of course do exist and we will discuss them in our next posts.