Face masks are a simple way to help prevent the spread of the new coronavirus through talking, coughing or sneezing, scientists and public-health specialists say. But they need to be worn properly.
While some types of masks are more effective than others, public-health officials say any face covering—even a bandanna—is better than nothing.
Here’s how different types of masks stack up, and how they are meant to be used.
Cut from different cloth
Common masks fall into three categories: cloth masks or coverings like gaiters, intended to prevent an infected person from spreading the virus by catching large droplets; surgical masks, with a more sophisticated design also meant to prevent the wearer from spreading diseases; and N95 masks, which protect the wearer as well, and fit tightly to the face.
Cloth
- Typically homemade
- Style and materials vary widely
- Prevents wearer from spreading disease
- Work in herd-immunity: the more wear masks,
the more effective they are
- Wash after use
Surgical
- Loose fit
- Prevents wearer from spreading disease
- Dispose after use
- Made from a material called polypropylene
N95
- Tight fit, must be fit tested
- Protects wearer if fitted properly
- Limited quantity
Cloth
- Typically homemade
- Style and materials vary widely
- Prevents wearer from spreading disease
- Work in herd-immunity: the more wear masks, the more effective they are
- Wash after use
Surgical
- Loose fit
- Prevents wearer from spreading disease
- Dispose after use
- Made from a material called polypropylene
N95
- Tight fit, must be fit tested
- Protects wearer if fitted properly
- Limited quantity
Fit vs. function
A good cloth mask filters well and is comfortable to breathe through.
A cloth mask should consist of three layers: an inner layer near the mouth that can get moist, a middle filtration layer and an outer layer exposed to the outside environment. Here are the materials for homemade masks that do this best, according to the World Health Organization, using a scale that combines filter quality and breathability. A higher rating is better.
Breathability and filtration rating
Polypropylene
Cotton (Knit)
Polyester (Knit)
Polypropylene
Cotton (Knit)
Polyester (Knit)
How a mask fits is as important as what it is made of.
How to put on a mask
Surgical Mask
1. Check for defects in the face mask, such as tears or
broken loops
2. Place one loop over each ear. Mask will contour to face,
but not as tightly as an N95.
3. Mask should sit on bridge of nose
1. Straps rest at the back of your head. An N95 will contour
tightly to face.
2. Mold metal strip to the shape of your nose
3. Re-adjust straps or nosepiece until a
proper seal is achieved
4. Place both hands over the respirator and breathe.
If there’s leakage, there is not a proper seal.
5. If you can’t get a proper seal, try a different N95 size
or model.
Surgical Mask
1. Check for defects in the face mask, such as tears
or broken loops
2. Place one loop over each ear. Mask will contour
to face, but not as tightly as an N95.
3. Mask should sit on bridge of nose
N95
1. Straps rest at the back of your head. An N95
will contour tightly to face.
2. Mold metal strip to the shape of your nose
3. Re-adjust straps or nosepiece until a
proper seal is achieved
4. Place both hands over the respirator and breathe.
If there’s leakage, there is not a proper seal.
5. If you can’t get a proper seal, try a different
N95 size or model.
Removing a mask properly is also important to prevent the spread of the virus.
Three Steps to Removing an N95 Mask
Do not touch the front of the N95 to remove your mask. This can cause contamination.
Pull the straps from the back of your head. Discard while making sure to avoid touching the respirator.
Discard Your Mask and Wash Hands
If you need to re-use an N95 mask, store it in a paper bag for five days. Then you can re-use it.
Professional grade
N95 masks filter out at least 95% of very small particles when worn properly, including droplets carrying viruses. Versions with a plastic valve at the center, which makes the mask easier to exhale through, are intended for industrial workers and offer protection only to the wearer.
True N95s aren’t easy to wear properly. They must have a tight seal to the face to ensure that all air goes through the filter instead of around the edges. But they offer the best protection against the coronavirus, which is why the WHO recommends these masks be reserved for health-care workers.
A manufacturer business name
or logo should be printed on
the mask
“NIOSH”name
should appear on
an official N95 respirator
Model number
N95 respirators manufactured
after September 2008, must
have a TC-Approval number
The LOT number is an identification
number that may also include the
date the mask was made. It’s
recommended, but not required.
1. “NIOSH”name should appear on an official N95
respirator
2. A manufacturer business name or logo should be
printed on the mask
3. Model number
4. N95 respirators manufactured after September
2008, must have a TC-Approval number
5. The LOT number is an identification number that
may also include the date the mask was made. It’s
recommended, but not required.
Write to Austen Hufford at austen.hufford@wsj.com
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July 28, 2020 at 09:22PM
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