Thursday, May 26

Is it time to ditch cloth face masks for FFP2 or next generation alternatives? | Coronavirus


During the early days of the pandemic, the choice was simple: Wear a reusable cloth mask or a disposable surgical mask. As the months have passed, the choice of face coverings and other forms of protection has multiplied, while the appearance of more transmissible variants has led some countries to require the use of filtering face masks (FFPs) in public spaces.

Although a face covering is no longer legally required in England, the government has suggested continuing to wear it in crowded, enclosed spaces where you may come into contact with people you don’t normally meet.

FFP2 masks filter at least 94% of 0.3-micron particles, covering most virus-carrying respiratory aerosols that remain in the air, and according to research published in Fluid Physics, are typically three times more efficient at filtering out larger particles, typical of those produced during speech, compared to the best three-layer cloth masks.

So is it time to ditch our cloth masks in favor of FFP2 or next-generation alternatives? And is it possible to do it without resorting to single-use masks?

Cloth masks

fabric mask
Photograph: Adrian Sherratt/The Guardian

Reusable cloth masks aren’t designed to block ultrafine particles like aerosols that carry viruses, but they do catch larger respiratory droplets, so they’re better than nothing. They also have the advantage of being washable, ideally in soapy water over 60°C (140°F), which reduces waste.

Although cloth masks are less effective at filtering, “given the myriad of parameters involved in disease transmission, we still don’t understand the degree to which that affects disease spread,” says Dr. Joshua Robinson, a physicist at the University of Bristol. who has been studying the performance of the mask. “If people are looking to improve the performance of their cloth masks, then improving the face seal in problem areas like around the nose will likely help.”

antibacterial masks

antibacterial mask
Photograph: Adrian Sherratt/The Guardian

Some FFP2 masks, like the Cradle Washable Multi-Purpose Mask (pictured) or the är Mask, feature a silver chloride-based coating called ViralOff, which claims to destroy 99% of viral particles within two hours. This would not sterilize the incoming air, but it could reduce the risk of the virus getting on your hands and transferring it elsewhere. Since the coating of the mask also destroys bacteria and fungi, it can also reduce the risk of “maskne”.

Robinson notes that the quality of the filter, including the electrostatic charging of the fibers, which increases the performance of the masks, is likely to degrade over time. Cradle said his mask’s ability to filter out 0.3-micron particles dropped from 98.7% to 96% after 100 hours of hand washing with mild detergent at 40C, line drying in between, meaning it would still meet the requirements of the FFP2 standard.

transparent masks

clear mask
Photograph: Adrian Sherratt/The Guardian

Helloface was founded to help people who are deaf or hard of hearing communicate, something that conventional face masks inhibit because they hide mouth movements and other facial cues. Their transparent medical mask is promoted as an alternative to surgical masks and contains antimicrobial and anti-fog elements. Although not designed for reuse, the plastic components are recyclable.

UV masks

ultraviolet mask
Photograph: Adrian Sherratt/The Guardian

Although it may look like Darth Vader is wearing it, UVMask is one of several masks and protective products being developed that incorporate UV-C light, a wavelength that inactivates viruses by destroying their protein coating, to purify incoming air and outgoing. It has not yet received regulatory approval, so it is not clear if this concept will work, according to the US Food and Drug Administration, there are limited published data on the wavelength, dose, and duration of UVC radiation required to inactivate Sars-CoV-2.

The mask also features two FFP2 filters, which will probably do all the heavy lifting, says Aaron Collins, an engineer who tests and reviews the masks. In his opinion, “what you have left is a gadget”.

Reuse of disposable masks

FFP2 mask
Photograph: Adrian Sherratt/The Guardian

Although it doesn’t say so on the package, many mask experts say that disposable FFP2 masks are safe to reuse, as long as you take a few precautions: only reuse your own mask; throw it away if it has been in close or prolonged contact with an infected person, or if it shows signs of blockage, difficulty breathing, or if the straps or mask lose their shape, meaning it no longer forms an airtight seal. with the face; and decontaminate it between uses. To do this, you need to hang it in a clean, dry place (not on a radiator) or store it in a breathable paper bag for five to seven days, while wearing a different mask.

The US Centers for Disease Control and Prevention says N95 (FFP2 equivalent) masks “can be used multiple times under crisis capacity strategies” – although he recommends replacing them after five uses. “My recommendation on reuse for the general public is a total wear time of 40 hours, or if the straps or mask lose their shape, affecting the fit to the face, whichever comes first,” says Collins.

Never spray masks with alcohol or disinfectant, which can damage fibers or damage lungs, or put disposable masks in a hot washer, dryer, microwave, or oven, which can also damage fibers. According to investigate at the FH Münster University in Germany, FFP2 folding masks can be safely decontaminated by heating them in an oven at 80°C for 60 minutes, or by sealing them in a freezer bag and boiling them for 10 minutes, although the elastic straps can be damaged and so it should be checked.

air purifiers

Air purifiers have long been used in hospital operating rooms to reduce the risk of post-surgery infections, but portable units are increasingly being deployed in schools and nursing homes on the assumption that they will reduce similarly the risk of coronavirus infections. Although they have been shown to reduce the amount of viruses in the air, in some cases even undetectable levels – these studies have been small and have not yet shown that air purifiers reduce the risk of infection, to what extent, or how best to implement them.

“They may work, but we need [this information] to make some sensible, rational, evidence-based decisions,” says Professor Alastair Hay of the University of Bristol, who is leading a study of portable air purifiers in nursing homes. It emphasizes that the presence of an air purifier should not be an excuse to relax other protection measures. “If it turns out that the other behaviors are really doing the heavy lifting, then you could end up doing the damage.”


www.theguardian.com

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