Facemasks: A Primer


(Photo courtesy: Raam Gottimukkala/Pixabay)


Why wear face masks and who should wear them?

SARS-CoV-2 (coronavirus from hereon), which causes COVID-19, is thought to spread from person to person, mainly when they are in close contact with one another. When an infected person talks, coughs, or sneezes, the droplets that are sprayed into the air may land in the mouths or noses of people who they are close to.

Not surprisingly, as the COVID-19 infection began to proliferate, so did the popularity of face masks, especially medical masks (surgical and masks and N95 respirators). In order to ensure that there is no shortage of medical masks for those who are on the frontline in the battle against the disease, the World Health Organisation (WHO) and governmental departments in many countries recommend that medical masks be worn only by (1) those who are sick and showing symptoms of COVID-19 and (2) those caring for people who have or are suspected to have the infection.

What about the rest of us?

The guidelines on whether the rest of us need facial protection have been evolving, particularly as we learn more about the coronavirus. In the past few weeks, several studies have shown that the coronavirus is even more dangerous than initially presumed because it can also spread surreptitiously. It can be spread by infected individuals who are asymptomatic – those who do not show symptoms – and by individuals who are pre-symptomatic – those who do not show any symptoms for the first few days of contracting the pathogen.
In response to these findings, many federal departments and organisations, including the Ministry of Home Affairs of the Government of India and the Center for Disease Control and Prevention (CDC) of the Department of Health and Services of the United States Government, are now urging, even insisting, that the rest of us too cover our noses and mouths – with cloth face masks – when we are in public places and workplaces.

What is the ideal material for a homemade mask?

While most fabrics that we would use for a DIY cloth mask have pores that are bigger than the coronavirus, the goal of using such masks is to prevent the transmission of water or mucus droplets that come out of our mouths and noses.

A 2013 study found that among household fabrics, dish cloth works best to capture bacteria and viruses, followed by cotton blend shirt fabric and 100% cotton tee shirt. A useful rule of thumb to adopt when choosing the appropriate material is to determine how much light it lets through – the lower the better. Another recent study has shown that using two layers of cloth is more effective than using a single layer. But it is also important to take into account the breathability of a fabric. A 100% cotton tee shirt was found to be far superior to the dish cloth, and could therefore be a good candidate for a DIY face mask material.

Once the material is chosen, how to make a cloth face mask at home?

There are many tutorials online about how to make a mask at home using material available in most households – some that use a sewing machine like this one from the Washington Post. But if you don’t have access to one, there are several sources which give you step by step instructions on how to make a mask with a machine, like this one from the CDC. The office of the Principal Scientific Advisor (PSA) to the Government of India has released a manual on face masks, one that also contains a detailed guide to making your own face mask, both with and without the use of a sewing machine. Our own website too has a useful infographic on making your own cloth face mask.

It would be useful to make at least two cloth masks per person so that at any given time you have access to at least one clean mask (masks have to be cleaned before reuse. See below for more details).

How do I wear a mask?

WHO has detailed recommendations on how to wear a mask. While these are meant for medical masks, many of them also apply homemade face masks. These recommendations could be important because masks themselves can be a source of infection when not used correctly. The PSA manual also provides instructions on how a homemade cloth mask should be handled. A concise list of dos and don’ts based on these two sets of recommendations is presented below:

1. Before wearing a mask, clean your hands with soap and water or an alcohol-based handrub.
2. Inspect the mask for holes and tears.
3. Identify the inside of a mask.
4. Once you put on the mask, make sure it sits snug on your face and the top portion moulds to the shape of your nose.
5. Ensure that it covers your nose and mouth completely with no gap between the mask and your face.
6. Do not touch your face while using it to avoid contamination. If you accidentally touch it, clean your hands with soap and water or an alcohol-based handrub.
7. To take off the mask, remove the strap or rubber band without touching the front.
8. After putting it away, clean your hands with soap and water or an alcohol-based handrub.
9. Do not share your face mask with others.

How to reuse a homemade cloth face mask?

The PSA manual tells us what we need to do in order to clean and sanitise homemade face mask:

1. Thoroughly wash the mask in soap and warm water and leave it to dry in hot sun for at least five hours. If you do not have access to the sun, follow Option 2.
2. Place the mask in water in a pressure cooker and pressure boil it for at least 10 minutes and leave it to dry. Adding salt to the water is recommended. In the absence of a pressure cooker, you may boil the cloth mask in hot water for 15 minutes. If you do not have access to a pressure cooker or are unable to boil it, follow Option 3.
3. Wash and clean with soap and apply heat on the mask for up to five minutes (you may use an iron).

Is there anything else to keep in mind when it comes to using homemade cloth face masks?

There is some evidence to suggest that a DIY cloth face mask reduces the likelihood of microorganisms being expelled to the surroundings by the wearer. But it is not a foolproof barrier. Besides, the coronavirus could also spread when one touches a surface or an object with the virus and then touches their face. So even when one wears a cloth face mask and takes the precautions listed earlier, all the other prescribed guidelines pertaining to social distancing and personal hygiene must be followed diligently.

Karthik Ramaswamy is a Visiting Scientist at the Indian Institute of Science.