Homemade face masks and the coronavirus outbreak

Ruler background Materials illustration

Make a mask

As the coronavirus pandemic spreads, some governments have advised citizens to create their own face coverings. Here’s how to make masks at home:

Some governments have advised citizens to create their own face coverings. Here’s how to make masks at home:


Slowing the spread

Like other coronaviruses, the newly identified China coronavirus is being transmitted from person-to-person via airborne droplets when an infected person breathes out, coughs or sneezes.

A mask can stop virus particles spreading from an infected person. Wider use could stop the spread of the virus from those who have no symptoms or have not begun to experience symptoms.

The most effective face covering to block the transmission of the novel coronavirus is the N95 respirator mask, according to at least one study. With those in short supply and reserved for protecting healthcare professionals, many people have turned to homemade masks to protect themselves and others.


Constructing with caution

Although face coverings can slow the spread of the virus, the most effective actions are to avoid being exposed to the virus, maintain social distancing and hand washing.

U.S. Surgeon General Jerome Adams cautioned that wearing surgical-type cotton masks may not protect healthy Americans from contracting coronavirus and may even put them more at risk, since people who wear masks were likely to touch their face to make adjustments.


Finding the fit

A 2013 study published in Cambridge University Press’ Disaster Medicine and Public Health Preparedness journal on the efficiency of face masks against an influenza outbreak recommended face coverings constructed with pillowcases and cotton t-shirts when factoring in filtering, fit and easy access to materials. The study tested two microorganisms that represented a range of sizes similar to influenza viruses.

Filtration efficiency against two microorganisms
Representing the size of influenza viruses which ranges from 60 to 100 nanometers, 2013

Scarf

100% cotton t shirt

Silk

Pillowcase

Linen

Cotton mix

Tea towel

Vacuum cleaner bag

Surgical mask

0

25

50

75

100%

Scarf

100% cotton t shirt

Silk

Pillowcase

Linen

Cotton mix

Tea towel

Vacuum cleaner bag

Surgical mask

0

25

50

75

100%

Scarf

100% cotton t shirt

Silk

Pillowcase

Linen

Cotton mix

Tea towel

Vacuum bag

Surgical mask

0

25

50

75

100%

Scarf

100% cotton t shirt

Silk

Pillowcase

Linen

Cotton mix

Tea towel

Vacuum cleaner bag

Surgical mask

0

25

50

75

100%

The exact size of novel coronavirus, SARS-CoV-2, is unknown, but tests at Wake Forest Baptist Health in North Carolina measured the percentage of particles 0.3 – 1.0 microns in diameter — the size of many viruses and bacteria — that were trapped in 13 different designs of homemade masks.

The tests found the most effective homemade masks were made with double-layer, high-quality, heavyweight “quilter’s cotton” cotton. But face coverings with a single layer of open weave cotton trapped as little as 1% of microscopic particles the same size of many viruses.

Percentage of particles blocked
0.3 – 1.0 microns in diameter, the size of many viruses and bacteria, 2020

Homemade masks range

1% to 79% filtration

N95 mask

0

25

50

Surgical mask

75

100%

Homemade masks range

1% to 79% filtration

N95 mask

0

25

50

Surgical mask

75

100%

Homemade masks range

1% to 79% filtration

N95 mask

0

25

50

Surgical

mask

75

100%

Homemade masks range

1% to 79% filtration

N95 mask

0

25

50

Surgical mask

75

100%

Not sure if your fabric is a good filter? Scott Segal, M.D., chair of anesthesiology at Wake Forest Baptist, has an easy solution. Hold your fabric up to a light – the more light blocked by the fabric, the more particles that are likely blocked – but make sure the thicker fabrics are breathable.

Designs should result in a good fit. Wake Forest Baptist Health didn’t test for fit, but testers preferred designs with ties to customise the fit versus those that rely on elastics or hair bands. Supports on the bridge of the nose could enhance the fit of the mask.

If the mask is performing well, it will stop the wearer from emitting corona-size viruses, so make sure it’s washable or disposable.

The bandana mask

Construction of this face covering from a bandana is simple and the materials are easy to come by. A bandana could be replaced by another piece of close-weaved cotton, and elastics could be swapped for string, ribbon or fabric strips. The folding of the single piece of fabric results in a two-layer protection for filtering particles.

What you'll need
Bandana or around 20-inch square cloth, elastics or hair ties
Here's how

Fold one end of the bandana towards the center.

Fold the other end to the center.

Both ends should be evenly folded

Place the rubber bands around the sides about 6 to 7 inches apart.

Fold the bandana inwards again.

Fold the sides into the middle.

Fold one end of the bandana towards the center.

Fold the other end to the center.

Both ends should be evenly folded

Fold the sides into the middle.

Place the rubber bands around the sides about 6 to 7 inches apart.

Fold the bandana inwards again.

Fold one end of the bandana towards the center.

Fold the other end to the center.

Both ends should be evenly folded

Fold the bandana inwards again.

Fold the sides into the middle.

Place the rubber bands around the sides about 6 to 7 inches apart.

Fold one end of the bandana towards the center.

Fold the other end to the center.

Fold the bandana inwards again.

Both ends should be evenly folded.

Place the rubber bands around the sides about 6 to 7 inches apart.

Fold the sides into the middle.

The t-shirt mask

The mask pattern from an old t-shirt takes advantage of easy-to-access and low-cost materials. Tests at Wake Forest Baptist Health found that masks made from high-quality and ticker t-shirts performed well at filtering microns a similar size to that of the coronavirus, but a single layer of cotton isn’t the best defense.

What you'll need
T-shirt, scissors
Here's how

Cut a cross-section of the t-shirt about 7 inches from the bottom.

Cut out one side

of the fabric.

Cut the ends to

make tie strings.

Ready to fit ties around the face.

Cut a cross-section of the t-shirt about 7 inches from the bottom.

Cut the ends to make tie strings.

Cut out one side of the fabric.

Ready to fit ties around the face.

Cut a cross-section of the t-shirt about 7 inches from the bottom.

Cut out one side of the fabric.

Ready to fit ties around the face.

Cut the ends to make tie strings.

Cut a cross-section of the t-shirt about 7 inches from the bottom.

Cut out one side of the fabric.

Cut the ends to make tie strings.

Ready to fit ties around the face.

The shield mask

In order to relieve public demand for surgical face masks, a Hong Kong task force of research institutions tested and designed a 3-layer unconstructed medical face mask. Like the water-resistant nature of a surgical mask, the shield’s plastic outer layer defends against droplets from sneezing and coughing, and the task force reports that the paper towel and tissue layers filter 90% effectively as surgical masks.

What you'll need
Transparent plastic file folder or sun visor, kitchen paper towel, 3- or 4-ply tissue, hole punch or stapler, binder clips, plastic coated wires, rubber bands, adhesive tape, scissors, pair of glasses
Here's how

Fold the paper in half.

Stick the paper clip or a plastic coated wire to the top of the mask.

Put the binder clips on either side of the spectacle frames.

Fold in the sides and staple to make sure the rubber bands hold in place.

Place the rubber bands around the sides of the paper about 6 inches apart.

Clip the ends of the folder to the frame and wrap it around the spectacles.

Fold the paper

in half.

Stick the paper clip or a plastic coated wire to the top of the mask.

Put the binder clips on either side of the spectacle frames.

Fold in the sides and staple to make sure the rubber bands hold in place.

Place the rubber bands around the sides of the paper about 6 inches apart.

Clip the ends of the folder to the frame and wrap it around the spectacles.

Fold the paper

in half.

Stick the paper clip or a plastic coated wire to the top of the mask.

Place the rubber bands around the sides of the paper about 6 inches apart.

Put the binder clips on either side of the spectacle frames.

Fold in the sides and staple to make sure the rubber bands hold in place.

Clip the ends of the folder to the frame and wrap it around the spectacles.

Fold the paper in half.

Stick the paper clip or a plastic coated wire to the top of the mask.

Place the rubber bands around the sides of the paper about 6 inches apart.

Put the binder clips on either side of the spectacle frames.

Fold in the sides and staple to make sure the rubber bands hold in place.

Clip the ends of the folder to the frame and wrap it around the spectacles.

The stiched rectangle

With access to a sewing machine, this simple pattern allows the wearer to wash and reuse the mask without reconstructing the pattern. The mask has the advantage of a two-layer construction, and string ties allow for easy adjustment. A consistent secure fit is difficult to achieve without support on the bridge of the nose

What you'll need
Two 10” by 6” rectangles of cotton fabric, two 6” pieces of elastic (or rubber bands, string, cloth strips, or hair ties), scissors, sewing machine, needle and thread
Here's how

Fold over the long sides ¼ inch and sew a hem line.

Cut out two 10 x 6 inch rectangles.

Stack the rectangles.

Loop the ties around the ears and adjust to fit the face.

Run elastic or string through the hem on short sides.

Fold over the short sides ½ inch and sew

Fold over the long sides ¼ inch and sew a hem line.

Cut out two 10 x 6 inch rectangles.

Fold over the short sides ½ inch and sew.

Stack the rectangles.

Loop the ties around the ears and adjust to fit the face.

Run elastic or string through the hem on short sides.

Cut out two 10 x 6 inch rectangles.

Stack the rectangles.

Fold over the long sides ¼ inch and sew a hem line.

Fold over the short sides ½ inch and sew.

Loop the ties around the ears and adjust to fit the face.

Run elastic or string through the hem on short sides.

Cut out two 10 x 6 inch rectangles.

Stack the rectangles.

Fold over the short sides ½ inch and sew.

Fold over the long sides ¼ inch and sew a hem line.

Loop the ties around the ears and adjust to fit the face.

Run elastic or string through the hem on short sides.

The sewn inset

Using inserted HEPA filters, nose bridge support in the filter pocket and adhesive seal, UnityPoint Health believes this 3-layer mask can achieve similar levels of filtration as the N95 mask. Wake Forest Baptist Health tested coffee filters as an insert and found it did not improve performance and vacuum bags hindered breathing, but other materials may improve filtering.

What you'll need
Cotton fabric, hair ties, double-sided skin adhesive, scissors, sewing machine, needle and thread
Here's how

Sew together curved edges of the 2 mouth pieces.

Sew curved edge of face piece.

Sew edge of entire mask.

Match front sides of fabric.

Match cheek and mouth pieces and sew a 1-inch tack along the overlap.

Turn mask inside out through pocket opening.

Fold fabric over tie and sew.

Add hair tie to each side.

Match cheek and mouth pieces and sew a 1-inch tack along the overlap.

Sew together curved edges of the 2 mouth pieces.

Sew curved edge of face piece.

Add hair tie to each side.

Turn mask inside out through pocket opening.

Sew edge of entire mask.

Match front sides of fabric.

Fold fabric over tie and sew.

Sew together curved edges of the 2 mouth pieces.

Sew curved edge of face piece.

Match cheek and mouth pieces and sew a 1-inch tack along the overlap.

Match front sides of fabric.

Fold fabric over tie and sew.

Add hair tie to each side.

Turn mask inside out through pocket opening.

Sew edge of entire mask.

Sew together curved edges of the 2 mouth pieces.

Match cheek and mouth pieces and sew a 1-inch tack along the overlap.

Sew curved edge of face piece.

Match front sides of fabric.

Sew edge of entire mask.

Turn mask inside out through pocket opening.

Add hair tie to each side.

Fold fabric over tie and sew.

Endorsing the masks

The World Health Organization said that medical masks should be prioritised for health workers, but it opened the door to greater public use of homemade masks or other mouth coverings as a way to reduce the spread of the coronavirus.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, who is at the forefront of the U.S. fight against the coronavirus outbreak, said that Americans should cover their face if they have to go out in public, but they should still stay isolated as much as possible.

The United States Center for Disease Control recommends the use of cloth face coverings to help reduce transmissions, and Austria, Germany, Switzerland, Czech Republic, Morocco and Israel have all made the wearing of face masks in public compulsory as an additional defense against spreading the coronavirus.

Social distancing and isolation are considered the primary defender against the spread of the virus until a vaccine is developed.

Sources: Disaster Medicine and Public Health Preparedness via Cambridge University Press; Wake Forest Baptist Health; U.S. Centers for Disease Control and Prevention (CDC); Hong Kong’s Consumer Council; UnityPoint Health Cedar Rapids

Editing by Jon McClure and Michael Collett-White