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Face masks that you make at home or buy online are believed to provide a degree of protection against getting sick from the coronavirus, in as much as it can keep larger particles from spraying into the air when you cough, spit or sneeze. But what about the tinier particles that many homemade masks and coverings aren't as good at stopping?

And why have attitudes changed so quickly, with wearing a face mask in public places even mandatory in some areas? Is it recommended to wear masks any time you go outside, or only in some places? Should you wear face masks even when lockdown lifts and cities reopen?

We don't have answers to every question. But with the coronavirus causing over 3.3 million cases and over 235,000 deaths worldwide, people are turning to homemade masks in an attempt to slow the spread of the COVID-19 disease.

This article updates frequently, as advice and information about homemade masks and the coronavirus continue to evolve. It's intended as a resource to help you understand the current situation as presented by organizations such as the CDC and American Lung Association, but shouldn't serve as medical advice.

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How can wearing nonmedical masks in public help?

For months, the Centers for Disease Control and Prevention recommended medical-grade face masks for people who were presumed to be or confirmed to be ill with COVID-19, as well as for medical care workers. But spiking cases across the US and especially in hotspots like New York, Rhode Island, Michigan, Louisiana and Arizona have proven that current measures haven't been strong enough to flatten the curve.

There's also data that there may be some benefit to wearing a homemade mask in crowded places like the supermarket, versus no face covering at all. Social distancing and hand-washing are still paramount (more below).

Shortly after the CDC changed its recommendation to wear masks, American Lung Association Chief Medical Officer Dr. Albert Rizzo said this in an emailed statement:

The wearing of the masks by all individuals can give some degree of barrier protection from respiratory droplets that are coughed or sneezed around them. Early reports show that the virus can live in droplets in the air for up to one to three hours after an infected individual has left an area. Covering your face will help prevent these droplets from getting into the air and infecting others.

"WHO has been evaluating the use of medical and non-medical masks for #COVID19 more widely.



Today, WHO is issuing guidance and criteria to support countries in making that decision"-@DrTedros #coronavirus — World Health Organization (WHO) (@WHO) April 6, 2020

Homemade masks may help protect others from you

According to the American Lung Association, one in four people infected with COVID-19 might show mild symptoms or none at all. Using a cloth face covering when you're around others can help block large particles that you might eject through a cough, sneeze or unintentionally launched saliva (e.g., through speaking), which could slow the spread of transmission to others if you don't know you're sick.

"These types of masks are not intended to protect the wearer, but to protect against the unintended transmission -- in case you are an asymptomatic carrier of the coronavirus," the American Lung Association says in a blog post that discusses wearing homemade masks (emphasis ours).

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#DYK? CDC’s recommendation on wearing a cloth face covering may help protect the most vulnerable from #COVID19. Watch @Surgeon_General Jerome Adams make a face covering in a few easy steps. https://t.co/bihJ3xEM15 pic.twitter.com/mE7Tf6y3MK — CDC (@CDCgov) April 4, 2020

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What the CDC says about homemade face masks today

The most important takeaway from the CDC's message is that covering your face when you leave the house is a "voluntary public health measure" and must not replace proven precautions like self-quarantine at home, social distancing and thoroughly washing your hands.

The CDC is the US authority on protocols and protections against COVID-19, the disease caused by the coronavirus.

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In the CDC's words, it "recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g. grocery stores and pharmacies) especially in areas of significant community-based transmission." (The emphasis is the CDC's.)

The institute says not to seek out medical or surgical-grade masks for yourself and to leave N95 respirator masks to health care workers, opting instead for basic cloth or fabric coverings that can be washed and reused. Previously, the agency considered homemade face masks a last resort in hospitals and medical facilities.



Keep reading for more on the CDC's original stance on homemade masks.

The right way to wear a face covering or cloth face mask

The most important thing is to cover your entire nose and mouth, which means that the face mask should fit underneath your chin. The covering will be less effective if you remove it from your face when you're in a crowded store, like to speak to someone. For example, it's better to adjust your covering before you leave your car, rather than while waiting in line at the supermarket. Read on for why fit is so important.

Can you reuse your face mask?

Homemade masks and coverings made from cloth fabric are machine-washable. Medical-grade masks ideally are single-use, though in certain hospital environments, the severe shortage of N95 masks is making procedural exceptions a necessity. The FDA approved an emergency sterilization procedure for N95 masks in medical environments only. Here's what you need to know about mask cleaning and reuse.

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N95 masks vs. other masks: Facial fit and certification



N95 respirator masks are considered the holy grail of face coverings, and the one considered by medical professions to be the most effective at protecting the wearer from acquiring the coronavirus.

N95 masks differ from other types of surgical masks and face masks because they create a tight seal between the respirator and your face, which helps filter at least 95% of airborne particulates. They might include an exhalation valve to make it easier to breathe while wearing them. Coronaviruses can linger in the air for up to 30 minutes and be transmitted from person to person through vapor (breath), talking, coughing, sneezing, saliva and transfer over commonly touched objects.

Each model of N95 mask from each manufacturer is certified by the National Institute for Occupational Safety and Health. N95 surgical respirator masks go through a secondary clearance by the Food and Drug Administration for use in surgery -- they better protect practitioners from exposure to substances such as patients' blood.

In US health care settings, N95 masks must also go through a mandatory fit test using a protocol set by OSHA, the Occupational Safety and Health Administration, before use. This video from manufacturer 3M shows some of the key differences between standard surgical masks and N95 masks. Homemade masks are unregulated, though some hospital websites point to preferred patterns that they suggest using.

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Handmade face masks: Cotton and elastic

Homemade face masks can be fast and efficient to make at home, with a sewing machine or sewn by hand. There are even no-sew techniques, like using a hot iron, or a bandana (or other cloth) and rubber bands. Many sites provide patterns and instructions that use multiple layers of cotton, elastic bands and ordinary thread.

By and large, the patterns contain simple folds with elastic straps to fit over your ears. Some are more contoured to resemble the shape of N95 masks. Still others contain pockets where you can add "filter media" that you can buy elsewhere.

Be aware that there isn't strong scientific evidence that the masks will conform to the face tightly enough to form a seal, or that the filter material inside will work effectively. Standard surgical masks, for example, are known to leave gaps. That's why the CDC emphasizes other precautions, like washing your hands and distancing yourself from others, in addition to wearing a face covering in crowded areas and coronavirus hotspots when you go out in public.

James Martin/CNET

What homemade masks were used for first (not COVID-19)

Many sites sharing patterns and instructions for homemade masks were created as a fashionable way to keep the wearer from breathing in large particles, like car exhaust, air pollution and pollen during allergy season. They were not conceived of as a way to protect you from acquiring COVID-19. However, the CDC believes these masks could help slow the spread of the coronavirus since other types of masks are no longer widely available.

One site, CraftPassion, includes this disclaimer:

Due to recent coronavirus attacks across the world, I have been receiving a lot of requests on how to add nonwoven filter inside the face mask. Disclaimer: this face mask is not meant to replace the surgical face mask, it is a contingency plan for those who have no avail to surgical mask in the market. Proper use of a surgical mask is still the best way to prevent virus infection.

3M/Screenshot by Jessica Dolcourt/CNET

CDC's original stance on homemade masks

Along with the World Health Organization, the CDC is the authoritative body that sets guidelines for the medical community to follow. The CDC's position on homemade masks has changed throughout the coronavirus outbreak.

On March 24, acknowledging a shortage of N95 masks, one page on the CDC website suggested five alternatives if a health care provider, or HCP, doesn't have access to an N95 mask.

Here's what one CDC site had to say about homemade masks then:

In settings where face masks are not available, HCP might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort [our emphasis]. However, homemade masks are not considered PPE, since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face.

A different page on the CDC site appeared to make an exception, however, for conditions where no N95 masks are available, including homemade masks. (NIOSH stands for the National Institute for Occupational Safety and Health.)

HCP use of non-NIOSH approved masks or homemade masks In settings where N95 respirators are so limited that routinely practiced standards of care for wearing N95 respirators and equivalent or higher level of protection respirators are no longer possible, and surgical masks are not available, as a last resort, it may be necessary for HCP to use masks that have never been evaluated or approved by NIOSH or homemade masks. It may be considered to use these masks for care of patients with COVID-19, tuberculosis, measles and varicella. However, caution should be exercised when considering this option.

Now, the CDC advocates for all civilians to wear a face covering when they leave the house.

Know the limits



It's worth emphasizing again that sewing your own face mask may not prevent you from acquiring the coronavirus in a high-risk situation, like lingering in crowded places or continuing to meet up with friends or family who don't already live with you.

Since the coronavirus can be transmitted from someone who appears to be symptom-free but actually harbors the virus, it's crucial to the health and wellness of people over 65 and those with underlying conditions to know which proven measures will help keep everyone safe -- quarantine, social distancing and hand-washing being the most crucial, according to experts.

For more information, here are eight common coronavirus health myths, how to sanitize your house and car, and answers to all your questions about the coronavirus and COVID-19.