Wearing Face Coverings ?

Whether or not to wear a face covering is an important decision when Covid-19 is active in your area. Better safe than sorry is a good guide here. Many countries and states and cities are requiring them in some situations. 

To understand why face masks might work, it is important to look at how the virus that causes Covid-19 spreads in the first place.

Once it has infected someone, the Sars-CoV-2 virus responsible for the disease hijacks their cells to replicate itself. As it multiplies, these new virus particles then burst out of the cells and become suspended in the bodily fluids in our lungs, mouth and nose. When an infected person coughs, they can send showers of tiny droplets – known as aerosols – filled with the virus into the air.

A single cough can produce up to 3,000 droplets. There are fears the virus can also be spread simply through speaking. One recent study showed that we spray thousands of droplets invisible to the naked eye into the air just by uttering the words “stay healthy”.

Once out of our mouths, many of the larger droplets will quickly settle onto nearby surfaces while smaller ones remain suspended in the air for hours, where they can be breathed in. While the behaviour of the virus-filled droplets in rooms with air conditioning and outside environments are less well understood, they are thought to settle on surfaces more quickly in disturbed air. There are also some reports that the coronavirus can spread through ventilation systems in buildings.

 

The Sars-CoV-2 virus has been found to survive in these aerosol droplets for at least three hours, according to one study by virologist Neeltje van Doremalen and her colleagues at the US National Institute of Allergy and Infectious Diseases, Hamilton, Montana. But a more recent, but as yet unpublished study, has found that the Sars-CoV-2 virus is still infectious for more than 16 hours after being suspended in aerosol droplets. It found the virus was “remarkably resilient in aerosol form” compared to other similar coronaviruses they studied.

Together, they suggest that in the right conditions, the virus can linger in the air for several hours and still infect people if breathed in. And in indoor environments, they seem to be particularly prone to spreading through the air.

An unpublished analysis of 318 outbreaks of Covid-19 in China showed that it was most commonly transmitted in indoor environments, particularly in people’s homes, but also on public transport, in restaurants, cinemas and shops. They found just one example where the virus appeared to have been transmitted while people were outside.

 

Genetic material from Sars-CoV-2 has also been detected in the air in toilets and rooms used by people infected with Covid-19. One study of a cluster of cases that occured in a restaurant in Guangzhou, China, suggests that in poorly ventilated spaces the virus can spread to people sitting in the immediate vicinity through airborne aerosol droplets.

Face masks could help to reduce transmission in the community particularly if used in public transport and crowded areas.

A recently published study looking at the effectiveness of face masks to prevent the spread of the virus from infected people. It found a standard surgical face mask was enough to considerably reduce the amount of virus escaping in the breath and coughs of people infected with different respiratory viruses, including a mild type of coronavirus, influenza and a rhinovirus that causes the common cold.

 

One of the proposals for lifting lockdowns is that we use mass testing along with contact tracing and quarantine, to get ahead of infections in the community. If you are identified as an infected person, the health department can trace your family members, your social contacts and your occupational contacts, but it is very difficult to trace who you were sitting next to on the bus or train.

If we can limit transmission in these kinds of locations, it could really be a big help.

One of the reasons widespread, public face mask wearing is so important with Covid-19 has to do with the prevalence of asymptomatic carriers who can still spread the virus to others. It is estimated that anywhere from 6% to almost 18% of those infected can carry the virus without developing symptoms. Add to this an incubation period of around five days, but up to 14 days in some cases, before symptoms develop and even those who do go on to show signs of being contagious can spread the virus to a lot of people before they start to fall ill.

This makes it particularly difficult to suppress transmission in the community. But if everybody is wearing face masks, that would mean infected and asymptomatic people are also wearing masks. That could help to reduce the amount of virus which gets into the environment and potentially causes infections.

Even wearing a damp homemade mask can reduce the number of droplets each of us emit while we speak, according to a study by researchers at the US National Institutes of Health, Bethesda, Maryland.

 

So, while face masks might help those already carrying the virus from passing it to others, can they also protect the uninfected from breathing it in?

Certainly the ability of specialised, disposable masks like the N95 respirator and the equivalent FFP-2 respirator mask in Europe to filter out particles from the air is high. They are designed to passively filter out 95% and 94% of airborne particles respectively – down to the size of 0.3 micrometres across – as the wearer breathes.

Their performance with blocking viruses from entering, however, is more mixed. Some viruses can be as small as 0.01 micrometres, while researchers have reported the coronavirus that causes Covid-19 is 0.07-0.09 micrometres in size. Respiratory viruses, however, tend to be suspended in aerosol droplets, which can range in size from 0.1-900 micrometres, so blocking these is often more important.

Some older studies have suggested that smaller viruses than might be expected can slip through the N95 filter, but they have been found to be effective at blocking the influenza virus.

And there is some research to suggest these respirator masks are effective when it comes to protecting people against Covid-19. One analysis of health workers in China showed that those who wore N95 respirators did not become infected with the virus, despite caring for highly-contagious patients. This is one of the reasons why these masks have been deemed so important for frontline healthcare workers.

 

The concern is that, if the general public buy up all of the already short supplies of these masks, it will leave these crucial workers, who are the most likely to be exposed, unprotected and vulnerable. The World Health Organization has urged the general public not to wear these masks in order to secure supplies for health workers, and this has also been the rationale behind the reluctance of many governments to encourage the public to wear masks.

There are also some who fear that face masks can induce a false sense of security in those who wear them. One recent unpublished study from researchers at Yale University suggests that in US states where madates have been introduced for face mask wearing in public, people appear to be spending 20-30 minutes less time at home and make more visits to commercial locations such as shops following the change in the rules.

 

Another potential issue with asking the public to wear these masks is that they require training to fit properly. If they are not correctly fitted, the seal around the mouth and nose can still allow viral particles to slip around the side. Facial hair can also affect their performance as it disrupts the seal. The US Centers for Disease Control and Protection (CDC) has published a helpful guide for anyone sporting facial hair and looking to wear face masks – a neat “soul patch”, a pencil moustache or Zappa-style trim should be fine. Those sporting designer stubble, a flamboyant Dali or full Garibaldi might need to consider a shave.

But there are simpler alternatives available too. One recent, but yet to be peer-reviewed, study found a 3M surgical mask – the kind worn by surgeons in operating theatres – could keep out almost 75% of particles down to a size of 0.02 micrometres. While far less effective than an N95 respirator, a surgical mask can still help to reduce the number of particles breathed in. But by cutting a hole in the end of a stocking and wearing that over the mask, it was possible to improve the mask’s ability to cut out particles to 90%.

“Surgical masks, unlike N95 respirators, are designed to fit loosely,” says Loretta Fernandez, an environmental chemist at Northeastern University, in Boston, Massachusetts, who was one of those involved in the study. “This allows some air to go around the mask to the breathing zone rather than through the mask material.” They found that the addition of “nylons” on the outside of the mask helped to reduce this.

 

But with demand for surgical masks also high, many members of the public are being forced to make their own alternatives. There are already a wide range of designs available online for do-it-yourself mask makers, with most using cotton fabric to create a pocket that a filter of some kind can be placed in. Some suggest using vacuum cleaner bags, others add coffee filters between two bandanas or insert folded pillow cases.

Yang Wang, an environmental engineer at Missouri University of Science and Technology, and one of his students built a few examples of these masks and found that using fabrics with a higher thread count worked better. A cotton bandana was the least effective, followed by a woolen scarf, but a 600-thread-count pillowcase folded four times could filter out around 60% of the particles.

Masks made from allergy-reducing air conditioning filters and vacuum cleaner bags were found to work best, almost matching the performance of an N95 respirator.

There is a lot of potential for fabric masks and particularly masks which incorporate non-woven materials like those used in some dust mops. There is no reason why surgical masks should be the ‘best’ type of masks to wear in the community, but some fabrics have too many ‘holes’ and would not perform well.

Fernandez and her collaborator Amy Mueller, an engineer at Northeastern University, also examined the effectiveness of different homemade masks. The most effective used multiple fabric layers, although they fell some way short of N95 and surgical masks. Adding a nylon on top to clinch the mask onto the face, however, did increase the effectiveness to the point where some homemade designs were able to keep out 80% of the particles.

 

 

 

 

 

 

 

Our advice:

1. Follow and obey the relevant local, state and national laws regarding face coverings (and self-isolating, quaranteening, social distancing, rules and laws and advice, etc.).
2. We believe that if you are outdoors: unless your are in a medium or high population density area or time/place combination, like a protest, march, parade, a busy sidewalk street or square, or on a crowded beach or park, an outdoor concert or a sporting event (and we recommend against doing all of these currently), you probably do not need to wear a face covering. 
3. Indoors, unless you can maintain at least 2 meters or 6 feet of social distancing at all times, AND you don't plan on staying indoors for too long, nor in one place for too long, we recommend that you should wear a face covering. Don't stay in one place indoors if possible, do what you have to do and get back outdoors (or home) and away from other people, which is safer.
4. Respirators are best (they actually can filter our 95% or more of the virus, thus protecting the wearer as well as others), high quality masks are next-best, surgical masks are next-best and cloth face coverings are much better than nothing. (Masks and face coverings give some protection to the wearer, and some to others, as they effectively stop spray or aerosol transmission of the virus). Make sure to check for fraud, counterfeit goods, shoddy goods and price gouging: U.S. CDC and the 3M Company. See our mask guide at the end of this article.
5. Be aware of and stay alert to crowded indoor spaces with no ventilation. They are dangerous. Air flow indoors should be directed vertically, perferably up from the floor to the ceiling and vented outdoors at the highest possible level.
6. Try not to stay in one place if there are other people around. Now is not a good time to be hanging out with other people unless you know they are negative for the virus - which you can't know unless you know them personally. Even people you know personally might not be safe, as they often won't even know if they have the virus or not themselves, since there are so many asymptomatic cases!
7. Never touch your face covering, except by the straps. Never touch the outside face of your face covering or mask. Never touch your face, and never stick a finger in your nose, mouth or eye areas.
8. Store your face covering in a paper or plastic sack if you are going to re-use it, with the outside face down. Close the bag, and put it in  a safe place, and use it every second or third day. Any virus on the mask should be dead if kept in a bag for 24 hours. Be aware that non-washable masks and respirators have effective times that should be respected if possible - many are only effective for 8 hours of use, for example.
9. It's OK to briefly take off your mask to smile at a new acquaintance (for 1 quick second) as long as you don't have a cold and are not coughing or sneezing. Remove face coverings to blow your nose and to sneeze only if you have adequate tissue paper to completely cover your mouth and nose area and can do so without contaminating anyone. Tissue paper must be disposed of in the trash as must all disposible face coverings. Do not remove your mask to cough - you MUST cough inside it. Sneezing, if a dry sneeze, should also be done inside the mask with it on. Do not share masks, and once on, the mask should be left on for as long as it is actively needed. Avoid putting on and remove the face covering many, many times per day. The face covering MUST cover your nose as well as your mouth, and it should never be pulled down to allow your nostrils to be outside and uncovered. Covid-19 is in the respiratory path which definitely includes the nose! Also - DO NOT TOUCH YOUR MASK OR FACE COVERING while wearing it. Only adjust it by its straps. Thank you for your cooperation.

If you can't buy a 3M respirator or a surgical mask, and are going to buy a consumer grade face covering or make your own, here are some important ways to separate the wheat from the chaff - to separate good masks from poor ones.

Identifying a good, protective mask from a bad one can be confusing. To make sure you're not flying mask-blind, it's important to keep abreast of WHO and Centers for Disease Control and Prevention mask guidelines, which are regularly updated. Right now (July 25, 2020), masks with three layers are the recommendation.

And there are some mask facts and hacks that can be helpful:

One of the most fundamental things to get right about your mask is fit.

You want your mask to fit snugly over your mouth and nostrils, up to the nose bridge, with little excess air escaping from the sides when you exhale. But you also want to be able to breathe, he explains. A good rule is as snug as you can go without finding it hard to breathe.

Make sure you get this right. One study found that "gaps due to improper fit resulted in over a 60% decrease in the filtration efficiency."

Then there's the question of mask material.

You can just hold your mask up to a bright light source or use your phone flashlight. Stretch it. Can you see right through it? If you can, that's a bad sign.

You can also check labels for preferable fabrics and materials; recent studies have shown that 100% cotton with high to moderate yarn count (that is, a heavier, coarser yarn) performed best in mask tests conducted. While the process for figuring out yarn count can be a little tricky, the general rule is the thicker the fabric, the higher the yarn count.

In short, you want a mask that fits you well, and that has cotton with high yarn counts and possibly with multiple layers, which many masks today do offer.

Once you've found a great-fitting mask fashioned with a breathable and protective material, there are some simple DIY steps to fortify your mask.

You can make a small slit (between mask layers) and add paper towels. Or buy yourself some OLY fun (a craft product) and place a layer in the mask — this can bring it up to a surgical mask's level of protectiveness.

Adding a static charge to the outer layer of a polyester mask by rubbing it with a latex glove for 30 seconds can also be effective. The reason: COVID-19 particles have a charge, so adding static can help create an extra layer of repelling protection.

If you're going to buy a mask, look at it carefully. Don't buy things that claim to be 'specially treated' with copper or other irons that kill bacteria. The virus isn't bacterial, and those treatments haven't been proven to be effective with the novel coronavirus as of yet.

An interesting and decent test is the candle test: Can you blow out a candle from 1 foot (30 cm) with your mask on? If you can, the mask isn't very good.

Look at the CDC's guide here.