Although it is agreed that the use of a mask is essential to stop the spread of the new coronavirus, scientists are still trying to understand how best to use the accessory to ensure protection. For example, you may have heard that masks with three layers of fabric are more effective, right?
Health experts have been saying it for months: Wearing a mask is just one tool in the fight against COVID-19, but as new variants emerge, some suggest that wearing just one may not be enough. If you buy a face mask to protect yourself and others from COVID-19, make sure it is a three-layer mask. You may have heard this recommendation before, but researchers have now found an additional reason why three-layer masks are safer than one- or two-layer alternatives.
While this advice was originally based on studies showing that three layers prevent small particles from passing through the pores of the mask, researchers have now shown that three-layer surgical masks are also most effective at preventing large droplets from coughing or sneezing from being atomized into smaller droplets. These large cough droplets can pass through the single- and double-layer masks and be atomized into much smaller droplets, which is especially important because these smaller droplets (often called aerosols) can stay in the air longer. The researchers studied surgical masks with one, two and three layers to demonstrate this behavior.
Layered masks protection
The team finds that single- and double-layer masks provide protection by blocking some of the fluid volume of the original drop and are significantly better than wearing no mask at all. They hope their findings on ideal mask pore size, material thickness and layering could be used by manufacturers to produce the most effective mask designs. said Abhishek Saha, professor of mechanical and aerospace engineering at UC San Diego and co-author of the paper.
Here’s a problem. Models of droplet physics have shown that while these large droplets should fall to the ground very quickly due to gravity, these now smaller, 50-80 micron droplets that come through the first and second layers of a mask linger in the air where they can spread to people over longer distances. If you use a double mask, make sure the fit is good and that you can breathe through it reasonably well. Those are the concerns I would have about putting too many layers on, so breathing through the mask could be compromised.”
Our 3-layer performance face mask is designed to give you all day comfort and a better fit. This reusable face mask consists of three soft, breathable layers for all-day use on the job site. The textured design separates the mask from your mouth so you can move and breathe easier. The breathable face mask has an antimicrobial treatment that prevents odor-causing bacteria, and is also moisture-wicking to stay cool and dry quickly. This three-layer face mask features comfortable, adjustable ear loops and a flexible nose bridge that easily adjusts to fit your face.
WHO on 3-layer masks
This spring, the World Health Organization (WHO) recommended that health care workers, people infected with COVID-19, and people caring for people with COVID-19 wear medical face masks to protect against the virus. On 5 June, WHO published updated guidance on the use of masks, recommending them for a wider range of people and providing information on the best type of non-medical fabric masks to use.1 The WHO now recommends that you always wear a three-layer fabric mask when you are in public places where social distancing is impossible. WHO emphasizes that masks can help prevent the spread of COVID-19.
WHO recommends avoiding materials that are stretchy – they have poor filtration capacity and are sensitive to washing at high temperatures – and those made of silk or gauze. The study found that respirators and multi-layer masks provide better protection than single-layer masks. “This finding is important to inform the proliferation of homemade fabric masks, many of which are single-layered. A well-designed cloth mask should have water-resistant fabric, multiple layers, and a good fit for the face…. Universal use of face masks could allow safe lifting of restrictions in communities seeking to resume normal activities and could protect people in crowded public places and within households,” Professor Raina MacIntyre of the Kirby Institute, University of New South Wales in Australia, said in an accompanying commentary. She was not involved in the study. The World Health Organization has recommended wearing a mask with three to four layers since June. The same number of layers is already preferred by the Quebec government. However, the province’s Ministry of Health and Social Services has clarified that this only applies to non-medical masks on the market and not homemade ones.
Effective layer masks
Not all face masks are equally effective. Boomer Naturals tells us why its 3-ply masks are better than the rest. A mask or face shield should consist of at least three layers: two layers of tightly woven fabric, such as cotton or linen, and a third (middle) layer of filtering fabric, such as nonwoven polypropylene, the agency’s website now says.The filters add an extra layer of protection against COVID-19 by blocking smaller infectious particles, it says. It is recommended to use this filter fabric as a third layer or to place a disposable filter between the two layers of a mask.
The team tested the ability of one- to three-layer masks to filter droplets comparable in size to those emitted by coughing or sneezing. Using a droplet generator and a high-speed time-lapse camera, the scientists found that larger respiratory droplets can be atomized as they pass through the first few layers. The expert adds that physical models have proven that the smallest droplets (about 50-80 microns in size) remain in the air and can spread more easily because they are not attracted to the ground in the same way as larger particles. The three-layer sterilized disposable type 1 surgical masks are suitable for use for up to 4 hours and are indicated for private use or in the workplace (please observe the applicable regulations on social distancing). Intended for the general public where no special protective equipment (PPE) is required.