Is it time to ditch sheet masks in favor of other face coverings like FFP2 or next generation alternatives? The choice of protective equipment during the COVID-19 pandemic has grown like mushrooms after rain. The Guardian published a comparison of various masks, their effectiveness against coronavirus.
In the early days of the coronavirus pandemic, writes The Guardian, the choice was simple: either wear a reusable cloth mask or a disposable surgical mask. But within months, the choice of face coverings and other forms of protection has exploded, and the emergence of more transmissible options has prompted some countries to mandate filtered face masks (FFPs) in public places.
FFP2 masks filter at least 94% of 0.3 micron particles, covering most of the virus-carrying respiratory aerosols that linger in the air. And according to a study by Dr. Richard Sear of the University of Surrey and colleagues, such masks are typically three times more effective at filtering out the larger particles that form during speech than the best three-layer fabric masks.
So, isn’t it time to ditch sheet masks in favor of FFP2 or next generation alternatives? And can this be done without resorting to disposable masks? These are the questions that The Guardian asks at the start of its review.
Reusable cloth masks are not designed to block ultra-fine particles such as virus-carrying aerosols, but they do catch larger respiratory droplets, so protection is better than nothing. They can also be washed – ideally in soapy water above 60°C – which reduces waste.
Although cloth masks are less effective at filtering, “given the large number of parameters involved in disease transmission, we still do not understand the extent to which this affects the spread of the disease,” says Dr. Joshua Robinson of the University of Bristol. who studies the effect of masks. “If people are looking to improve the performance of their sheet masks, then improving the fit to the face in problem areas, such as around the nose, will most likely help.”
Some FFP2 masks have a silver chloride-based coating called ViralOff that is said to kill 99% of viral particles within two hours. This protective equipment does not sterilize the incoming air, but may reduce the risk of the virus getting on your hands and spreading it to other places. Because the mask cover also kills bacteria and fungi, it can also reduce the risk of masknee (a skin condition caused by long-term wearing of nose and mouth protection products, i.e. masks and respirators).
Dr. Joshua Robinson notes that the quality of the filter, including the electrostatic charge on the fibers that makes the masks more effective, can degrade over time. One manufacturing company stated that its mask’s ability to filter 0.3 micron particles decreased from 98.7% to 96% after 100 minutes of hand washing in a mild detergent at 40°C with an intermediate in-line dryer, which means that the mask will still comply with the FFP2 standard.
Transparent masks were created to help people who are deaf or hard of hearing communicate, while regular face masks prevent this because they hide mouth movements and other facial expressions. A transparent medical mask is advertised as an alternative to surgical masks and contains antimicrobial and anti-fog elements. Although it is not designed to be reused, the plastic components are recyclable.
Masks with UV protection
While you might look like Darth Vader in it, The Guardian writes, the ultraviolet mask is one of several masks and protective products in development that include ultraviolet light that inactivates viruses by breaking down their protein coat to purify incoming and outgoing air. These masks, writes the British edition, have not yet received regulatory approval, so it is unclear whether this concept will work – according to the U.S. Food and Drug Administration, published data on the wavelength, dose and duration of UV radiation, needed to inactivate the Sars-CoV-2 coronavirus are few.
The mask also comes with two FFP2 filters that will probably do all the hard work, says Aaron Collins, engineer who tests and validates the masks. In his opinion, “what you have left is a gadget.”
Re-wearing disposable masks
Although not stated on the packaging, many mask experts claim that re-wearing disposable FFP2 masks is safe – provided some precautions are followed: only re-wear your own mask; dispose of it after close or prolonged contact with an infected person, or if it shows any signs of blockage, becomes more difficult to breathe through, or if the straps or mask have lost their shape, i.e. it no longer forms a snug fit with the face. You should also decontaminate the mask between wears, writes The Guardian. To do this, hang it in a clean and dry place (not on a battery) or store it in a breathable paper bag for five to seven days while you wear another mask.
The U.S. Centers for Disease Control and Prevention (CDC) says N95 masks (equivalent to FFP2) “may be used multiple times as part of a crisis opportunity strategy,” although it is recommended that they be replaced after five wears. “My reuse recommendation for the general public is 40 hours of total wear time, or if the straps or mask lose their shape, affecting facial fit — whichever comes first,” says Aaron Collins.
Masks should never be sprayed with alcohol or disinfectants, which can damage fibers or lungs. Also, do not put disposable masks in the washing machine, dryer, microwave or hot oven – this can also damage the fibers. According to research from the University of Münster in Germany, FFP2 foldable masks can be safely disinfected by heating them in an oven at 80°C for 60 minutes, or by placing them in a freezer bag and boiling for 10 minutes, although the elastic straps can be damaged, so they should be check.
Air purifiers have long been used in hospital operating rooms to reduce the risk of post-operative infections, but handheld devices are increasingly being used in schools and nursing homes in the belief that they will similarly reduce the risk of contracting the coronavirus. Although they have been shown to reduce the amount of virus in the air—to undetectable levels in some cases—such studies have yet to prove that air purifiers reduce the risk of infection.
“They may well work, but we need information to make smart, rational, evidence-based decisions,” says Professor Alastair Hay of the University of Bristol, who is leading the study on portable air purifiers in nursing homes. He emphasizes that the presence of an air purifier should not be used as a reason to weaken other protective measures.