If made with the right household materials, you can create a mask that may be as effective as a medical mask and, in some ways, similar in blocking efficiency to an N-95 respirator (although not a replacement for an N-95), according to several laboratory studies. Masks can be used alone or, for increased protection, particularly for the eyes, with a face shield
Below we discuss the details of masks and how to make them. We also identify what seem to be best disposable filter materials
If you would prefer to buy a mask, we have identified several brands that appear to meet the specifications of the World Health Organization (see Best Cloth Masks You Can Buy
Why you should wear a mask -- and why it should be an efficient one
Along with social distancing, a mask provides additional protection from infecting others as well as preventing exposure. A review of studies found that transmission of SARS-CoV-2 and related coronaviruses was 82% lower with physical distancing of 1 meter (3.3 feet) or more, compared with shorter distances, and protection might increase with additional distance. Face mask use could result in an 85% reduction in risk of infection versus no face mask, with stronger associations for N-95 or similar respirators, while surgical masks and multi-layered cotton masks were less effective but offered more protection than single-layer masks (Chu, Lancet 2020).
An analysis of rates of growth of COVID-19 infection in U.S. states found that the mandated use of masks in public issued by 15 states in April and May, 2020 was associated with a decline of about 1% in the daily COVID-19 growth rate within the first week of the mandates and a 2% decline 21+ days after mandates were issued. Although the effect is modest, the researchers estimated that by May 22, 2020, 230,000 to 450,000 COVID-19 cases may have been averted due to the mandates (Lyu, Health Aff 2020
As wearing a mask may reduce the amount of virus to which a wearer is exposed, it has been postulated that even if a mask-wearing person becomes infected, the reduced viral load to which they were exposed may mean that they suffer a milder disease. Supporting this theory is a study that showed that hamsters protected with a surgical mask partition were less likely to become infected with SARS-CoV-2 than those without the partition, and those that did get sick had milder illness. In addition, on cruise ships with COVID-19 outbreaks, the majority of infected patients (81%) were asymptomatic on a ship that had provided masks to all passengers and staff compared to only 18% of cases being asymptomatic on a cruise ship without masking (Gandhi, J Gen Intern Med 2020
; Gandhi, N Engl J Med 2020
Any benefit to wearing masks at home?
Although CDC guidelines do not currently include the use of face masks at home, the rate of transmission from one household family member to another was 79% lower when members wore face masks prior to the first member developing COVID-19 symptoms, according to a study of 124 families in Beijing in which there was at least one infected person. Overall, there was a 23% rate of transmission of COVID-19 from an infected family member to another, but this was no lower when mask wearing began after the first member developed symptoms. These results are consistent with the fact that viral load is highest two days before symptoms and on the first day of symptoms. Daily use of disinfectants reduced transmission by 77%. Transmission rates were four times higher if the primary case had diarrhea and 18 times higher when there was frequent daily close contact (less than 3 feet apart). The researchers recommended use of face masks in families in which a member has been at risk of getting infected. In China, over 70% of transmission occurred within families (Wang, BMJ Global Health 2020).
Best combination of materials for making a mask
The World Health Organization
(WHO) recommends using three layers of fabric for non-medical, cloth masks in order to achieve the best combination of filtration efficacy and breathability:
1. Innermost layer:
Hydrophilic material (i.e., one that can absorb moisture, such as cotton or cotton blends)
2. Middle layer:
Hydrophobic material (i.e., repels moisture) of synthetic non-woven material such as polypropylene or a second cotton layer which may enhance filtration or retain droplets.
3. Outermost layer:
Hydrophobic material (e.g., polypropylene, polyester, or their blends) which may limit external contamination from penetration through to the wearer's nose and mouth.
(See Best Cloth Masks You Can Buy
for our review of masks for sale that appear to meet the WHO requirements)
Note that polypropylene, a material often used to make disposable surgical masks, has an electrostatic charge which can improve the filtration efficiency of masks. Polypropylene "spunbound" is sold in fabric and many other retail and online stores under brand names such as Oly*fun and Pellon. Polypropylene is sold in different weights (measured in grams per square meter or GSM). Most commercially manufactured surgical masks are made of 3-ply 25GSM. Polypropylene materials between 25 and 40 GSM tend to have similar filtration efficacy and breathability, while polypropylene 60 GSM has a higher filtration efficiency but less breathability (Zhao, Nano Lett 2020
). Be aware that some forms of polypropylene should not be machine washed.
See below for a more detailed discussion of the filtration efficacy of various cotton and synthetic household fabrics.
How cotton and other household fabrics compare in blocking coronavirus
The first study, from the University of Illinois at Urbana-Champaign, found that many household fabrics can be as effective as the material in surgical masks for blocking droplets of sizes known to carry the COVID-19 (SARS-CoV-2) coronavirus. The blocking efficiency of a commercial medical mask was found to be 96.3%, while the blocking efficiency of a used dish cloth (85% polyester and 15% nylon) was slightly better -- 97.9%. In addition, most household fabrics were more breathable than the material in a medical mask. The dish cloth, for example, was twice as breathable as the medical mask (Aydin, medRxiv 2020 --preprint
). (See the CDC website
to learn how to make a cloth face covering.)
A study at the University of Chicago and Argonne National Laboratory found that tightly woven, high-thread count cotton (600 thread-per-inch (TPI) sheet by Wamsutta
) was more effective in filtering large droplets (similar to larger-sized SARS-CoV-2 droplets) than loosely woven cotton with a lower thread count (quilters cotton, 80 TPI), while fabrics with an electrostatic charge (such as silk and chiffon) were best for blocking aerosols -- the smaller sized droplets that remain suspended in air for extended amounts of time. Using layers of both fabrics, together
, was most effective for blocking both large and small droplets. For example, two layers of 600 TPI cotton fabric had a large particle and small particle blocking efficacy of 99.5% and 82%, respectively, but one layer of 600 TPI cotton combined with two layers of chiffon (90% polyester, 10% spandex from Jo-Ann Stores
) had a large particle and small particle blocking efficacy of 99.2% and 97% -- which, at low airflow rates (i.e., when not all air is drawn through the mask) is nearly as good as a properly-fitted N95 mask for blocking large particles and better than the N-95 with respect to small particles, of which only 85% are blocked by an N-95 mask). However, as emphasized in a published correction to the study, it is not known how efficient this fabric combination will be at normal or high rates of airflow when made into a fitted mask, i.e., when there are no leaks and all air flows directly through the mask, particularly when one is engaged in high levels of exertion.
The researchers also found that small holes or leaks around the edges of the fabrics could decrease the blocking efficacy by 50% or more, and emphasized the importance of a good fit (snug and without gaps) (Konda, ACS Nano 2020
). [Note: An illustration in the study shows the electrostatic layer of fabric as the inner layer when fabrics were combined. However, ConsumerLab contacted the author of the study who suggested that electrostatic fabric (such as chiffon) may be best used as the outer layer of the mask to avoid humidity from the nose or mouth, which could interfere with the electrostatic properties, but emphasized that was his suggestion, not something that was tested in the study.]
In another study, researchers at Florida Atlantic University tested masks made from common household fabrics, as well a typical "cone" mask (often sold at pharmacies) to see how well they worked to stop droplets using a simulated model of coughing (a mannequin head through which liquid was manually pumped). Without any covering, droplets from the simulated cough traveled an average of 8 feet. With a bandana (single-layer, elastic T-shirt material, 85 threads per inch) droplets traveled an average of 3 ft. 7 inches, with a folded cotton handkerchief (as shown in this instructional video
featuring the U.S. Surgeon General), 1 ft. 3 inches, and with a cone mask (CVS Cone Face Mask), 8 inches. The most effective mask was a stitched cotton mask (using two-layers of cotton quilting fabric, 70 threads per inch), with which droplets traveled just 2.5 inches. The researchers noted that "healthcare professionals trained properly in the use of high-quality fitted masks will not experience leakage to the extent that we have observed in this study. However, leakage remains a likely issue for members of the general public who often rely on loose-fitting homemade masks." (Verma, Phys Fluids 2020
Rather than focus on how far droplets travel, researchers at Duke looked at how well different masks block droplets during speaking. A fitted N95 mask without a valve was most effective in retaining droplets, with less than 1% of droplets being transmitted. The next most effective, in order, were a 3-layer surgical mask, a cotton-polypropylene-cotton "apron" mask, a 2-layer polypropylene mask, a 2-layer cotton pleated mask, and then an N95 with a valve.
The Duke researchers also found that two masks offered little protection: A double-layer bandana was only slightly more effective than using no face covering at all, while the worst face covering was a "gaiter" style neck fleece (often worn during running or sports) that showed a 10% increase
in the number of droplets. The researchers suggested that the neck fleece material breaks larger liquid droplets into smaller droplets than can more easily be dispersed into the air (Fischer, Sci Adv 2020
— includes photos of the masks but no details about origin or brands). However, tests conducted by researchers at Virginia Polytechnic Institute found that, when measuring droplets that dispersed in an outward direction at a distance of about 1 ft. (30 cm), neck gaiters (one made of thin, 100% polyester (Chaos) and the other, a thicker, microfiber gaiter made of 87% polyester and 13% elastane (Cirque)) worked as well as a cloth mask (a no-sew mask made of cotton T-shirt material), blocking 100% of larger droplets (> 20 microns), 90% of droplets 5 microns in size, and 50% of 0.5 micron aerosols. They were somewhat less efficient than the cloth mask at blocking smaller aerosols, although when the thinner gaiter was doubled over, it blocked about 90% of droplets and aerosols (0.5 to 5 microns) (Pan, Virginia Tech PDF 2020)
Best Materials for Making Your Own Mask Filter
As discussed above, the WHO recommends
that the middle layer of a cloth mask be made of a synthetic, nonwoven fabric such as polypropylene, or a second layer of cotton (high thread count cotton has been shown to have better filtration efficacy than lower-thread cotton). Many cloth masks that you can buy online come with a "filter pocket" as the middle layer, which you can buy pre-made filters for, or add your own. We've reviewed common materials for making mask filters, including Filti Face Mask Material and Medline Dry Baby Wipes, as well as materials such as polypropylene and other non woven fabrics (100% polypropylene, Pellon Sew-In Interfacing and Oly*fun), cotton and quilter's cotton.
Sign in as a member
or join now
to see our reviews and more details about materials for making your own mask filters.
Best Cloth Masks You Can Buy
If you prefer to purchase a cloth mask, we reviewed many masks sold online. We identified several masks that we believe best meet the WHO guidelines and/or are constructed with materials that offer a good combination of filtration efficacy and breathability
. We also considered features that can affect fit and comfort, such as adjustable/bendable nose wires and adjustable straps, which can be important for people who wear glasses or hearing aids. We also identified a mask to accommodate beards and use when singing. We also identified two masks with clear panels to better enable lip reading by others.
Our list starts with our overall Top Pick
, followed by our next favorites, as well as masks for those who need clear panels. In our review of masks, we considered those from Allet, Atelier, Giftington, Proper Cloth, Rafi Nova, Tom Bihn, Vertex, Vida, Vistaprint, and masks sold on Etsy.
Be aware that there is a shipping fee for most masks, calculated before check out based on location and/or other factors. Most companies provide an estimated time for the product to ship, but delivery time will depend on the shipping option you choose. ConsumerLab.com derives no revenue from sales of these products.
(To see our list of the best cloth masks you can buy, sign in
. If you are not a ConsumerLab member, join now
How to reduce air leakage around a mask
A way to reduce air leaks was suggested by a study, at Northeastern University in Boston, which showed that pulling an 8 to 10-inch tube of nylon (cut from a queen-sized nylon stocking) down over a regular mask and to the top of the neck. This significantly prevented air leakage around the mask and improved particle filtration efficiency, making the combined masking nearly as effective as an N-95 respirator which, unlike a medical mask, has an electrostatic charge and is specifically designed to prevent air leakage (Mueller, medRxiv 2020 --preprint
; Godoy, NPR.org 4/22/20
How to clean a cloth mask
Cloth masks can be washed in a washing machine. They can also be cleaned using heat
, but a washing machine is preferred.
Potential carbon dioxide buildup
If you make a well-fitted mask with high blocking efficiency, it may share the same potential that N95 masks have to reduce oxygen intake and, over time cause carbon dioxide buildup inside the mask (Sinkule, Ann Occup Hyg 2013
). According to researchers at Stanford University
, N95 masks are "are estimated to reduce oxygen intake by anywhere from 5 to 20 percent. That's significant, even for a healthy person. It can cause dizziness and lightheadedness." However, a small study in the U.S. found that wearing an N-95 mask for up to one hour did not cause any significant adverse effects in healthy healthcare workers performing moderate activities, despite significantly decreased inhaled oxygen and increased inhaled carbon dioxide levels (Roberge, Respir Care 2010
). A representative from the CDC told Reuters.com
that "...the level of CO2 likely to build up in the mask is mostly tolerable to people exposed to it. You might get a headache but you most likely [would] not suffer the symptoms observed at much higher levels of CO2. The mask can become uncomfortable for a variety of reasons including a sensitivity to CO2 and the person will be motivated to remove the mask. It is unlikely that wearing a mask will cause hypercapnia [elevated blood levels of carbon dioxide]."
The CDC advises
that face masks should not be placed on children under the age of two, anyone who has trouble breathing, or anyone who would not be able to remove the mask without assistance.
N-95 vs. KN-95, KF94 and other respirators
Be aware that masks labeled as "KN-95" are not
N-95 respirators and their filtration
may not match that of N-95 masks. KN-95 masks may also not have a proper fit
to prevent air leakage and typically have "ear loops" rather than the head bands used on N-95 respirators. The CDC has published its own tests of many of KN-95 and related masks
, by brand, showing filtration levels as low as 13.6% to over 99%; however air leakage around the masks was not
tested, so a KN-95 mask filtering 99% may be inferior to an N-95 respirator that provides a proper fit even though its filtration efficiency need not be greater than 95%).
The CDC also publishes a list of approved N-95 respirators
, and the FDA has published a list of authorized N-95 respirators
from China that have not gone through the CDC (NIOSH) approval process but were approved in China. Note that 1) some products that had been on this list were later removed on May 7, 2020 after being tested by the CDC (NIOSH) and 2) these respirators lose their authorization if they have been decontaminated for reuse (apparently because they may contain cellulose, which may not be able to withstand authorized decontamination processes) (FDA announcement 6/6/20).
A study at the University of California, San Francisco found that after extended periods of use, a much higher percentage of health care workers using duckbill-shaped N-95 masks (made by Kimberly-Clark and Halyard) failed a "fit test" than those using dome-shaped N-95 masks (made by 3M): Failure rate was 70.6% with duckbill masks versus 27.5% with dome-shaped masks. A fit test is performed by having an individual indicate if they can detect a bitter taste introduced by a chemical in the air (Degesys, JAMA Letters 2020
A comparison of hospital facemasks showed that procedural and surgical masks had much lower filtration efficacies
, from 27% to 69%, than most commonly used N95 respirators which, even after decontamination and re-use, provided 95% efficacy or better. Two masks that were not NIOSH-approved but were authorized for use by the CDC (DTC-3X-1 and DTC-3X-2 from Dasheng) had, respectively, only 77% and 80% efficacy, and a KN95 mask (Guangdong Fei Fan KN95) had just 53% efficacy. Variability in mask performance was dependent on the tightness of the contact between the material and the facial skin and masks that tied around the head outperformed those with elastic ear loops
, noting that "ear loops may not provide adequate tension to maintain a tight fit during a typical range of motions" (Sickbert-Bennett, JAMA Intern Med 2020
According to the United States Department of Labor
, healthcare workers who are unable to obtain N95 respirators may use R95, R99, P95, P99, P100
and others respirators. Like N95 masks, these are expected to filter out a minimum of 95% of particles of the most penetrating size, and those ending in a "99" or "100" filter out at least 99% or 99.97%, respectively, of such particles but can be more difficult to breathe through. R95 and P95 masks are typically used for protection when working with oil-based substances like fuel, paints, solvents, or pesticides. N95s are not resistant to oil, R95s are "somewhat resistant" and P95s are "strongly resistant to oil or oil proof," as shown in the CDC's infographic
about these types of masks. If considering an alternative respirator, make sure it is NIOSH approved
. Respirators with exhalation valves should not be used when trying to protect others. (See a video demonstration by researchers at Florida Atlantic University of how aerosols can spread when coughing while wearing an N95 mask with a valve).
KF94 respirators from Korea are often promoted as the Korean "equivalent" to N95 respirators, but this is not quite accurate. Although they can have relatively high filtration efficacy, KF94 masks are considered "public use" respirators and are not held to the same performance standards as Korea's Special 1st class "occupational use" respirators (which are considered to be roughly equivalent to NIOSH approved N95 masks). KF94 respirators are designed to have a filtration efficacy of 94%, and CDC tests of one brand of KF94 found its filtration efficacy to be even higher (99.85 to 99.94%). However, unlike all NIOSH-approved N95s (which attach with head bands), KF94 respirators attach with ear loops, which, the CDC points out, may compromise their fit and efficacy. The CDC did not perform fit testing on the KF94s it tested and noted a lack of information about manufacturing quality control. In addition, unlike surgical N95 respirators, KF94 respirators are not considered fluid resistant (Kim, J Korean Med Sci 2020).
Are copper masks better?
Copper has been shown to inactivate a wide variety of bacteria and some viruses, typically within minutes to hours of contact, and a study found that SARS-CoV-2 (at about 72°F and 40% relative humidity) was undetectable on copper after four hours (van Dormalen, NEJM (correspondence) 2020
). There do not appear to be studies showing how effective masks made with copper or copper infused fabric are against SARS-Cov-2. However, preliminary research with other viruses suggests a possible benefit. A study funded by the maker of copper masks (Cupron
) for healthcare and institutional use, showed that an N95 mask with two added layers of copper oxide infused material (polypropylene fabric containing 2.2% weight/weight copper particles) had a similar filtering efficacy as a regular N95 mask, but was much more effective in inactivating human influenza A virus (H1N1) and avian influenza virus (H9N2) (Barkow, PLoS One 2010
). A University of Massachusetts Amherst microbiologist developed a reusable mask made of 99.95% pure copper mesh, which, according to a university news release
, was shown to "kill 90% of microbes within five minutes of contact." In Hong Kong, the government is distributing fabric masks to the public that contain copper, known as the CuMask+
(Parry, BMJ 2020
). According to the manufacturer, CuMask+
is made up six layers, "two of which are specially made with small quantities of copper." Tests
published by the company suggest it retains antiviral activity with up to 60 washes (handwashed with soap and cold water). If you use a copper-containing mask, be sure to clean it regularly and according to the product instructions: Bacteria and viruses can cling to dirt or other particles on copper, making it less effective (Grass, Appl Environ Microbiol 2011
Some concerns have been raised
about the safety of copper masks and the possibility of breathing in copper particles. While we don't have safety information for specific products, laboratory studies that measured the amount of copper released from copper oxide impregnated masks during 5 hours under simulated breathing conditions was far below the respiratory copper permissible exposure limit (PEL) set by the USA Occupational Safety and Health Administration ("OSHA") (Borkow, Curr Chem Biol 2012
What masks protect against wildfire smoke?
Cloth masks, including those with sewn-in or removable filters, should not be relied on for protection from wildfire smoke, according to the CDC. They protect against some of the larger particles in wildfire smoke, but not from smaller particles in smoke that can damage the lungs. In addition, one-strap paper dust masks and surgical masks, worn alone, are not recommended for wildfire smoke protection.
It is recommended that people who have to be outdoors in wildfire affected areas wear fit-tested, NIOSH-approved N95 or P100 respirators, and the CDC notes that properly fitted N95 respirators can "provide protection from wildfire smoke and from COVID-19 for the individuals wearing them." To help prevent the spread of COVID-19 to others, N95 masks without valves are recommended. If an N95 mask with a valve is your only option for wildfire smoke protection, consider covering the valve with tape or wearing a surgical mask over the N95 when around others, as recommended by John Balms, M.D. at UCSF.