- The World Health Organization now recommends that the general public should wear face masks during the coronavirus pandemic, and even describes what the masks should look like.
- According to the WHO, the “ideal” non-medical face mask has at least 3 layers.
- The WHO also explains which types of fabric have the greatest filtration efficiency.
Confusion reigned supreme in the early days of the novel coronavirus pandemic, but despite the fact that there is still plenty we don’t know about the virus and the deadly disease it causes, most of us are finally on the same page about what we can to do mitigate its spread. You should get a test if you don’t feel well, socially distance from others, wash your hands often, and, perhaps most importantly, wear a mask when you can’t socially distance.
Last Friday, the World Health Organization finally came around on face mask usage during the pandemic, updating its guidelines to suggest that governments should tell their citizens to wear masks in most public settings. The WHO still believes that “the widespread use of masks by healthy people in the community setting is not yet supported by high quality or direct scientific evidence,” but the pros of wearing masks outweigh the cons.
With that said, medical masks like these are always going to be the most effective, but they might not be readily available, and so the WHO has also created a set of recommendations for non-medical masks.
As the WHO notes, there are unlimited combinations of fabrics and materials being used to create masks during the pandemic, whether you’re making them yourself or buying them from a retailer. Some materials are better at filtering droplets than others, though, with cotton T-shirts and polypropylene at the top of the list.
The type of fabric you choose is important, but just as important is the number of layers the mask uses. The WHO says that a minimum of three layers is required for non-medical masks, depending on the material. Fabric cloths are said to provide 2-5 times increased filtration when folded into two layers, and 2-7 times when folded into four layers. Balancing filtration efficiency and breathability is key, but, put simply, more layers is better. The WHO even provided specific instructions for what the “ideal” non-medical mask should look like:
The ideal combination of material for non-medical masks should include three layers as follows:
- an innermost layer of a hydrophilic material (e.g. cotton or cotton blends)
- an outermost layer made of hydrophobic material (e.g., polypropylene, polyester, or their blends) which may limit external contamination from penetration through to the wearer’s nose and mouth
- a middle hydrophobic layer of synthetic non-woven material such as polyproplylene or a cotton layer which may enhance filtration or retain droplets.
The WHO may have taken its sweet time on face masks, but at least its belated guidance is comprehensive.
