Homemade face masks offer limited protection, but if used properly, they’re better than nothing

In Tokyo it was very normal to see people wearing face masks on the street and on public transit long before Covid-19. (Richard McGuire Photo)

The advice from health authorities on who should wear masks for protection and when is mixed. This article will outline the advice, look at the research and discuss how some people are are busy sewing masks either for themselves and their families or to provide them to emergency workers.

The BC Centre for Disease Control website gives this advice on masks:


“Masks should be used by sick people to prevent transmission to other people. A mask will help keep a person’s droplets in.
“It may be less effective to wear a mask in the community when a person is not sick themselves. Masks may give a person a false sense of security and are likely to increase the number of times a person will touch their own face (e.g., to adjust the mask).
“Health-care workers will wear surgical masks, eye protection and gowns in order to protect themselves and other patients. During health-care procedures in which aerosol sprays may be generated (for example, when giving certain inhaled medications), health-care workers should wear specialized masks.” – BC Centre for Disease Control
The Public Health Agency of Canada goes further, actually suggesting masks are “not recommended” for healthy people:


“If you are a healthy individual, the use of a mask is not recommended for preventing the spread of COVID-19.

“Wearing a mask when you are not ill may give a false sense of security. There is a potential risk of infection with improper mask use and disposal. They also need to be changed frequently.

“However, your health care provider may recommend you wear a mask if you are experiencing symptoms of COVID-19 while you are seeking or waiting for care. In this instance, masks are an appropriate part of infection prevention and control measures. The mask acts as a barrier and helps stop the tiny droplets from spreading you when you cough or sneeze.” – Public Health Agency of Canada

The U.S. Centers for Disease Control and Prevention (CDC) offers similar advice, also noting that masks are in short supply and should be saved for caregivers:

  • “If you are sick: You should wear a facemask when you are around other people (e.g., sharing a room or vehicle) and before you enter a healthcare provider’s office. If you are not able to wear a facemask (for example, because it causes trouble breathing), then you should do your best to cover your coughs and sneezes, and people who are caring for you should wear a facemask if they enter your room. …
  • “If you are NOT sick: You do not need to wear a facemask unless you are caring for someone who is sick (and they are not able to wear a facemask). Facemasks may be in short supply and they should be saved for caregivers.” – U.S. Centers for Disease Control and Prevention (CDC)

So the main arguments against using masks more widely are:

  • They give a false sense of security because they are of limited effectiveness;
  • When they are misused, they can actually increase the risk of infection;
  • They are in short supply and should be saved for those who really need them.

But masks are widely used by the general public in many other countries, especially in Asia. On a layover in Tokyo a few years ago, I was surprised to see a large percentage of people wearing surgical masks on public transit and on the street. And that was long before Covid-19. Are these people doing something ineffective?

What about all the people making masks on their sewing machines using widely available cotton fabric? It’s laudable that many of these people are making them for emergency workers, but it’s unclear how many will actually use them. Some hospitals in the U.S. are accepting these homemade masks, while others are not. Should people make masks for themselves?

It’s important to understand that different types of masks offer different levels of protection.

N95 masks are tight fitting and cover the nose and mouth. They are typically used by healthcare workers in conjunction with face shields. These masks screen out 95 percent of airborne particles and — importantly for healthcare workers — they offer reasonable protection against the virus when it’s transmitted as an aerosol, very tiny particles that remain in the air.

Surgical masks are looser fitting, disposable and they offer more limited protection. They may not be effective against aerosols, but they offer some protection from larger virus-containing droplets from coughing and sneezing. Healthcare workers use these more generally for protection when their work doesn’t require an N95 mask or one isn’t available.

Homemade, reusable cloth masks are less effective than either N95 or surgical masks because they are porous and unable to screen aerosols or smaller droplets. But some argue that in many situations, they are better than nothing.

UPDATE: I’ve added a link to this article by University of San Francisco research scientist Jeremy Howard in the Washington Post. Howard makes the argument that public health authorities are misguided when they tell people not to wear masks and that homemade masks can help. He backs his argument up with references to 34 scientific papers.

This article from CBC, “Masks and Covid-19: When, how and why you’d wear them,” discusses use of masks.

The reporter spoke to Dr. Michael Gardam, an infectious disease specialist and chief of staff for Humber River Hospital in Toronto, who made this observation:

Gardam said while wearing a mask makes ‘zero sense’ while walking down the street, there is a logic to using one if you’re forced to be in an enclosed space, such as public transit or a crowded grocery store (although many grocery stores are now limiting the number of customers inside).

It’s for those times when you’re forced to enter an enclosed space, such as a grocery store or pharmacy, where it might make sense for a healthy person to wear a homemade mask for that extra, but limited, protection.

For those with sewing machines who want to make masks, here are some articles on the internet offering “how-to” advice as well as discussing the effectiveness of different materials.

This article from Huffington Post offers good background and how-to information.

The article offers this advice:

“If you want to take the extra precaution of wearing a face mask when you’re not sick, the best thing you can do is make a mask for yourself ― don’t buy one and contribute to the shortage.”

This article from Smart Air Filters discusses the effectiveness of different materials for homemade masks. It is based on research done at Cambridge University in the UK.

The conclusion — although material such as vacuum bag filters may be a more effective screen, cotton is more breathable, and a cotton shirt offers about 69 per cent protection against 1-micron particles. The same cotton shirt material offers 51 per cent protection against 0.02-micron particles.

This article in LiveScience discusses some of the limitations and pitfalls of homemade cloth masks. Important: you should always wear the mask in the same orientation, that is don’t use the outer side on the inside. Making them different colours can help you know which side is which.

This video from Joann Fabric and Craft Stores shows the steps in sewing cloth face masks.

Once again, it is important to emphasize that homemade masks offer only limited protection. If you choose to use them, it is essential to continue with other protective measures such as social distancing and frequent and thorough hand washing.


Author: Richard McGuire

Richard McGuire is an Osoyoos photographer who worked at the Osoyoos Times between 2012 and 2018, first as reporter and then as editor. He has a long career in journalism as well as research, communication and management at the House of Commons in Ottawa and in the federal government.

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