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There are many steps that you can take to help prevent the spread of SARS-CoV-2, the new coronavirus that causes COVID-19. One of these is wearing a mask.

When it comes to masks, there are a variety of different options to choose from. These can include:

  • cloth masks
  • surgical masks
  • KN95 masks

Recently, you may have heard about something called double masking. Simply put, this is when you wear two face masks instead of one.

Should you be double masking? And if so, how can you do it safely? Continue reading to find out.

Double masking is when you layer one mask on top of another. This can have two advantages.

Better fit

Many types of masks don’t fit perfectly on your face. In fact, you’ve probably noticed that you feel air escaping through the sides of your mask when you breathe in and out.

This imperfect seal can not only allow respiratory droplets containing the virus to escape your mask, but it can also allow them in. Double masking can help to better prevent this from happening.

When you’re wearing two masks, the outer mask can apply gentle pressure to the edges of the inner mask. When this happens, the inner mask fits more closely against your skin and creates a better seal.

Increased filtration

SARS-CoV-2 is mainly spread through respiratory droplets that are made when someone who’s contracted the virus:

  • talks
  • coughs
  • sneezes

The material in a mask filters respiratory droplets containing the virus before you can inhale them.

The layers of a mask help to increase its filtration power. In fact, the Centers for Disease Control and Prevention (CDC) recommends using a face mask with at least two or three layers of fabric.

Adding a second mask can improve filtration even more. This is because it effectively doubles the layers of material that virus-containing respiratory droplets have to travel through before reaching your face and mouth.

Now that we’ve discussed double masking and its potential benefits, you may be wondering how you can wear two masks safely and effectively. Here are some tips to get you started.

  • Use the proper mask combination. The CDC recommends layering a cloth mask over a surgical mask.
  • Avoid other mask combinations. Some mask combinations may not improve fit or may make it hard to breathe. As such, avoid combinations of the following:
    • two surgical masks
    • a KN95 and any other type of mask
    • an N95 and any other type of mask
  • Test at home first. Try out your double mask at home before using it in public. Check for things like:
    • Fit. Make sure that the outer mask helps press the inner mask close to your face, forming a seal. To do this, cup your hands over your mask and feel for air escaping from the edges as you breathe.
    • Breathing. While breathing may require a little extra effort when you’re double masking, it shouldn’t make breathing difficult.
    • Vision. Make sure that your double mask doesn’t block your vision.
  • Evaluate the situation. If you can maintain a distance of at least 6 feet from others outside your household, a single mask can give good protection. However, a double mask can be beneficial when you’re:

The recommendation for double masking is based off the findings of a CDC study. This study looked at ways to improve mask fit to reduce exposure to SARS-CoV-2.

In the study above, coughing and breathing were simulated using a device that produced aerosol particles that the researchers could quantify after the experiment was completed.

Coughing simulation

In the coughing simulation above, researchers evaluated the effectiveness of:

  • a cloth mask alone
  • a surgical mask alone
  • a cloth mask covering a surgical mask (double mask)

Researchers found that when a cough was simulated, the double mask blocked 85.4 percent of the aerosol particles. This is compared to 51.4 percent and 56.1 percent for the cloth and surgical mask, respectively.

Breathing simulation

The breathing simulation investigated several situations using two models of a human head. One of the models generated aerosol particles (source) while the other was exposed to them (recipient).

Researchers found that:

  • When the source was wearing a double mask and the recipient was not, the aerosol exposure of the unmasked recipient was reduced by 82.2 percent.
  • When the recipient was wearing a double mask and the source was not, the aerosol exposure of the double masked recipient was reduced by 83 percent.
  • When both the source and the recipient wore a double mask, aerosol exposure was reduced by 96.4 percent.

Why you should double mask

In summary, researchers found two important things:

  1. When compared to either a cloth mask or a surgical mask alone, wearing a double mask was more effective at reducing aerosol exposure from coughing.
  2. Aerosol exposure through breathing was drastically reduced when both a source and recipient were wearing a double mask.
Healthline

In recent months, several variants of the new coronavirus have emerged throughout the world. Some of these variants can spread more easily between individuals.

One variant you may have heard of is B.1.1.7, the “United Kingdom variant.” Public health officials in the United Kingdom have reported that B.1.1.7 is about 50 percent more transmissible.

Additionally, according to a 2021 research review, another variant was recently identified in California during a surge in COVID-19 cases. The American Association for the Advancement of Science reports that in research yet to be published, the lab that identified this variant is reporting that, like B.1.1.7, it also appears to be more transmissible.

The rise of more transmissible variants means that taking good preventative measures is even more important than ever. Given its effectiveness, double masking can be an important tool in preventing the spread of these variants.

In addition to double masking, there are other ways that you can help to improve the effectiveness of your mask.

Prioritize layers

Multiple layers work to better shield your face from respiratory droplets that can contain the virus. When selecting a cloth mask, choose one that has at least two or three layers of fabric.

Add a filter to your cloth mask

Some cloth masks come with a built-in pocket into which you can place a filter material, such as a coffee filter or vacuum filter. You can also learn how to make a cloth face mask with a filter pocket here.

Choose a mask with a nose wire

Look for masks with a strip of wire located at the top. This wire can be bent to allow the mask to better fit over your nose. Using a mask with a nose wire can also prevent your glasses from fogging up, which can block your vision.

Try the knot and tuck method

This method can be used to improve the fit of surgical masks. It involves knotting the ear loops close to where they join to the mask and carefully tucking away any extra material. The CDC has instructions on how to do this.

Use a mask brace

A mask brace is a device that’s made from elastic material. It fits over a single cloth or surgical mask to help prevent air from escaping from the top and sides of the mask. You can even make a simple mask brace with three rubber bands.

Mask don’ts

While you can use several methods to make your mask more effective, some practices can lower the level of protection that a face covering provides.

To ensure that you’re well protected, avoid wearing a face covering that:

  • doesn’t completely cover your nose and mouth
  • is fitting improperly, either too tight or too loose
  • has only a single layer of fabric
  • is constructed using a loosely woven fabric, such as a mask that’s been crocheted or knitted
  • is made from a material that doesn’t breathe well, such as leather, plastic, or vinyl
  • has an exhalation vent attached to it
  • is a balaclava, scarf, or ski mask
Healthline

In addition to wearing a mask, it’s important to take additional steps to help prevent the spread of the new coronavirus. These include things like:

  • Washing your hands. Wash your hands frequently with soap and water, particularly after being in public or after coughing or sneezing. Use hand sanitizer with at least 60 percent alcohol if soap and water isn’t available.
  • Practicing physical distancing. Aim to stay at least 6 feet away from those outside of your household.
  • Avoiding certain areas. Try to avoid areas that are crowded or have minimal ventilation.
  • Disinfecting. Regularly disinfect high-touch surfaces in your home, such as door knobs, countertops, and light switches. The Environmental Protection Agency (EPA) lists disinfectants that are effective against the new coronavirus.
  • Getting tested. If you’re experiencing any of the symptoms of COVID-19, be sure to get tested and to isolate at home while you wait for your results.

Double masking is when you wear one mask on top of another. It helps improve the fit and filtration of your mask.

A CDC study found that double masking is very effective at preventing exposure to aerosols made by coughing and breathing.

If you’d like to try double masking, wear a cloth mask over a surgical mask. Avoid any other mask combinations.

It’s also a good idea to test your double mask at home first to make sure it fits and that your breathing and vision aren’t affected.

In addition to wearing a mask, it’s important to practice other preventative methods as well, such as handwashing and physical distancing. This is particularly important given the emergence of more transmissible viral variants.