Photographed By Kay Lau

If you’re living in the world today, no matter where you are you will have heard about the coronavirus called COVID19 and the need of face masks.  We might all have quiet opinions about what the situation really is, but at the end of the day the world keeps spinning and it is controlled by people who are listening to the findings of scientists.

Having the power to make decisions that will affect the lives of a country’s entire population, during the time of a health crisis, world leaders have a huge responsibility to make intelligent decisions that are in the best interests of their country’s future, and so when it comes to unfamiliar and unexplained patterns of rapid disease-creation which risk a continuing large scale of deaths and long term worries, it makes a lot of sense to listen to the individuals who have studied-to-be and who are qualified-to-be best informed about what is going on, what is causing it and how to affect it – scientists!

So when we tune into what scientists have to say about the COVID19 pandemic, we are paying attention to the information that decision makers have relied on or could rely on, to understand their decision making.  At this point in time it is scientists who are influencing the changes to the world that we know.

Not many people have realised that the wearing of face masks in public settings has contributed to a lessened need of a lockdown, it means that face masks are helping to keep the world moving.  In this writing the need of face masks is explained with reference to scientific views and goes on to provide information about the different kinds of masks being sold; their qualities and features, as well as touching on the recent government guidelines for keeping England and Wales moving.

The return to normal life by international states from the situation of lockdown involves a requirement for people to wear face coverings in public places – to prevent the spread of COVID19.  The USA’s Center for Disease Control and Prevention [CDC] and the World Health Organisation [WHO] have recommended cloth masks for the public, though during the earliest stages of the pandemic both organisations thought differently about face coverings.

Health experts confirm that there is clear evidence that masks can help with preventing the spread of COVID19 and that the more people wearing masks, the stronger the effect of controlling and preventing the disease.

Web Writer Nina Bai has introduced me to leading experts in the battle against COVID19: Epidemiologist George Rutherford Medical Doctor [MD] of the University of California, San Francisco and Infectious Disease Specialist Peter Chin-Hong MD also of the University of California, San Francisco.  Rutherford and Chin-Hong have made studies of the impact of face coverings on the COVID19 disease and have made their views available to the public.

What made the CDC change its mind about mask-wearing?

In explaining the CDC’s original guidance on face coverings, Chin-Hong points out that at the time the prevalence of COVID19 was relatively low.  “In the beginning it was thought unnecessary for the entire population to wear masks but that thinking reflects having not carried out enough testing – so what we had was a false sense of security.”

“The concern at the beginning, that there was an insufficient number of surgical masks and N95 respirators for healthcare workers, should not have prevented information about the benefits of masks – we should have been told to wear masks at the beginning,” said Rutherford.

“Culturally, the USA has been unprepared for wearing masks unlike the case in some countries of Asia where the practice is more common,” said Chin-Hong.“Even now some Americans are choosing to ignore CDC guidance and local mandates on masks.”

The CDC changed its mind and the factor which convinced the CDC to do so in favour of masks may have been COVID19’s rising prevalence and a clear realisation that pre-symptomatic and asymptomatic transmissions of the disease are possible and even common.  Studies have confirmed that viral loads peak in the days before symptoms begin and that speaking is enough to expel virus-carrying droplets from carriers of the virus.

“The biggest concern with COVID that calls for the use of masks is that it’s impossible to tell who’s infected,” said Chin-Hong.  “You can’t look into a crowd of people and say such and such a person should be wearing a mask; there’s a lot of infection which occurs before symptoms of the disease begin to show.  So everybody has to wear a mask.”

Is there evidence of mask-wearing being effective in the prevention of COVID19?

There are at least three lines of evidence which indicate the efficiency of face masks.

There’s a line which extends from the results of laboratory tests about respiratory droplets and the ability of masks to prevent them.  There’s a particular experiment where a high-speed video camera was used to realise that hundreds of droplets ranging from 20 to 500 micrometres could be generated and transmitted simply by stating a phrase, and that nearly all of these droplets were prevented from being transmitted when the mouth was covered by a damp washcloth.

In another study (based on flu sufferers) it was found that the wearing of a surgical mask reduced the amount of respiratory virus emitted in droplets and aerosols.

The strongest evidence in favour of masks comes from the study of real life scenarios.

“The most important evidence comes from the study of epidemiologic data,” said Rutherford.

Health Affairs recently published details of a study which compared the growth of the COVID19 rate before and after mask mandates in 15 states as well as the District of Columbia.  The study found that mask mandates achieved slowdowns of the daily COVID19 rate which became more apparent across time.  Results showed that the first five days following the mandate slowed the daily growth rate by 0.9 percentage-points in comparison to the previous five days.  At three weeks the daily growth rate had slowed by 2.0 percentage-points.

Another study focused on the COVID19 death rates across 198 countries and found that those with norms in favour of mask-wearing had lower rates of death.

“Two special cases provide compelling evidence that face masks can prevent transmission in high-risk scenarios,” said Chin-Hong and Rutherford.  (1) A man tested positive for COVID19 after flying from China to Toronto.  He had a dry cough and wore a mask during his flight, and all of the 25 other people closest to him tested negative for COVID19.  (2) During late May two hairstylists from Missouri had contact with 140 clients whilst sick with COVID19.  Everyone was wearing masks and not one of their clients tested positive for COVID19.

Masks protect their wearers or the people around them?

“There’s enough evidence to show that the best benefit of masks is for people who have COVID19, to prevent them from giving COVID19 to others, but even if you do not have COVID19 you can still benefit from wearing one,” said Chin-Hong.

Masks might be more effective for controlling the source of COVID19, because they can prevent large droplets that are ordinarily expelled, from evaporating into smaller droplets that can travel further.

“COVID19 could still be caught through the membranes in a person’s eyes – masks do not eliminate this risk,” said Rutherford.

How many people need to wear masks to reduce community transmission?

“What you want is 100 percent of people wearing masks, but you’ll settle for 80 percent,” said Rutherford.  In a particular simulation researchers predicted that 80% of the population wearing masks would do more to reduce COVID19’s spread than a strict lockdown.

A recent forecast by the Institute of Health Metrics and Evaluation suggests that 33,000 deaths could be avoided by 1 October if 95% of people wore masks in public.

“Even if you live within a community where few people wear masks, you would still reduce your own chances of catching the virus by wearing one,” said Chin-Hong and Rutherford.

Does the type of mask matter?

The materials that masks are made of have been studied, but for the wearers of masks it is probably comfort that will be the outweighing factor.

“The best mask is one that you can wear comfortably and consistently,” said Chin-Hong.  N95 respirators are only necessary during medical situations like intubation.  Surgical masks are generally more protective than cloth masks, and some people find they are lighter and more comfortable to wear.

“The fact is that any mask that covers the nose and mouth will be of benefit,” explains Nina Bai.

“The concept behind mask wearing is risk reduction rather than absolute prevention,” said Chin-Hong.

Chin-Hong and Rutherford have both cautioned against N95 masks with valves (typically used to prevent the inhalation of dust within the construction industry) because they do not protect others around the wearer.  The one-way valve closes when the wearer breaths in, but opens when the wearer breaths out – permitting unfiltered air and droplets to escape.  “Wearers of this kind of mask will also require a surgical or cloth mask over it,” said Chin-Hong.

San Francisco has confirmed that masks with valves do not comply with its policies for face coverings.

If we are wearing masks is there still a need for social distancing?

“Combating COVID19 is managed by three Ws: wearing a mask, washing your hands and watching your distance,” said Chin-Hong.  “Of these, wearing a mask is the most important as there is more evidence showing that inhaled droplets are the major source of COVID19’s transmission,” said Chin-Hong.

“I don’t wish to suggest a separation from social distancing and mask wearing – both are important, though mask wearing is the most important,” said Rutherford.

The capabilities of face coverings differ

The idea of creating homemade masks has existed since the issue of wearing face masks was raised.  There are mixed views about whether homemade masks is the right way to go in the battle against COVID19.  There’s a school of thought that says homemade masks could help to limit the transmission of the virus in busy environments where social distancing is less possible, such as within public transport and supermarkets.  But there’s another school which confirms that homemade masks can be expected to be many times less effective than medical masks at preventing the wearer from transmitting the virus, and of almost no use when it comes to protecting the wearer from the virus.  The concern is that a false confidence from wearing homemade masks increases the risk of the pandemic continuing.

The risk from faulty face coverings combined with the risks from a lack of good information for the public about the proper use of face masks creates a further risk of the pandemic continuing or returning, where the latter risk would be lessened if members of the public who wish to rely on homemade face coverings were made aware of their limitations.

Taking into account the risks mentioned by Julie Bissett, it is recommended that the public be educated on the proper use of face masks, including the features of the various kinds of medical face masks and how the public can identify face masks that have been manufactured to prevent the spread of viruses such as COVID19.

To identify a mask that could be used professionally for medical purposes notice the European Standard codes “EN 14683” and “EN 149” being mentioned on the packaging of items.  For the USA “ASTM” is said to be the equivalent notification.

Explaining the codes

EN 14683 refers to medical equipment “surgical mask”.  As per NF EN 14683, its design is for preventing its wearer from spreading droplets, but also for protecting its wearer from droplets produced by a person directly in front of them.  Depending on the circumstances it does not protect the wearer from inhaling very small particles in the air which potentially carry the virus.  There are three types of surgical mask: Type I (and I R) with bacterial filtering effectiveness of 95%, Type II with bacterial filtration effectiveness of 98% and Type IIR with 98% bacteria filtering effectiveness with a fluid-resistance feature.

EN 149 refers to respirators or a “filtering face piece” [FFP equipment].  As per NF EN 149, equipment of this kind is designed to protect the wearer from inhaling droplets and particles present in the air.  This kind of equipment is more restrictive than a surgical mask but it protects from inhaling infectious pathogens.  Available in shell, two-layers, three-layers, four-layers, and duck bill shapes, with or without an exhaling valve, with optional facial seals.  There are three categories of FFP which differ by their effectiveness: FFP1 which filter at least 80% of aerosols (with inward leakage < 22%); FFP2 which filters at least 94% of aerosols (with inward leakage < 8%); FFP3 which filters 99% of aerosols (with inward leakage < 2%).  Valve respirators are not appropriate for use against COVID19 or viruses generally since they do not prevent the release of exhaled respiratory particles from the wearer into the environment.

Below is information about face masks that have been designed for medical workers:

Face Mask TypeEuropean StandardBacterial Filtration EfficiencyNumber of LayersLifespan
Type IEN 1468395%3Single use
Type I REN 1468395%3Single use
Type IIEN 1468398%3Single use
Type II REN 1468398%3Single use
Type FFP2 (respirator)EN 149:200194%43-8 hours
Type FFP3 (respirator)EN 149:200199%4


With scientists explaining the need to avoid droplets and pointing to face masks as a way to achieve this, governments should be reminded about condensation and about circumstances when in crowded public places it would be desirable for windows to be closed, potentially increasing the humidity of the vicinity and the size of droplets in the air so much that masks will be incapable of preventing wearers from inhaling droplets.  Governments that take these situations into account early are more likely to prevent a pause in the progress made to prevent the COVID19 pandemic continuing or returning.  The scientists have played their part and found a solution which works under some circumstances.  Governments should also be interested in the limitations of proposed solutions.

Air Pollution

Air pollution is also responsible for causing a number of deaths each year in countries all around the world with no significant changes to this situation being expectant for many more years to come.  The use of face masks that are capable of filtering over 90% of the air received by its wearer has an additional benefit therefore.

When we think of air pollution we tend to think about the air outside, but there’s a kind of air pollution that can exist inside places that are visited.  Either way, a mask that helps to filter so much is a thing that is generally good for our health.

Recent Rules for England and Wales

The new rule for England and Wales is that face coverings must be worn within shopping environments from 24 July 2020.  The only exception to this rule is where the environment includes a place to stop and eat; for the purpose of eating a face covering would need to be removed, however, despite a shopping  environment having a place to stop and eat, if it is a person’s intention to only buy an item without stopping to eat, then they must be wearing a face covering and it must not be removed.  Pubs, restaurants and cafes are examples of shopping environments where a shopper may remove their face covering.

In England and Wales, as well as within shopping environments, a face covering must be worn whilst travelling on public transport.

What is PPE and where can I buy it?

By definition Personal Protective Equipment [PPE] refers exclusively to equipment that is designed to protect employed individuals from hazards that are inherent to their working environment.  It is the duty of employers to ensure that their employees are adequately protected whilst within the situations of their employment.

A “medical face mask” is defined as being a medical device which covers the mouth, nose and chin to ensure a barrier which limits the transition of infective agents between the hospital staff and the patient.  Within this writing a medical face mask is also referred to as a “surgical mask”.  Medical face masks comply with the requirements set within European Standard EN 14683:2014.

Being an item used professionally by medical workers to prevent them from hazards, the “medical face mask” is a kind of PPE.

To buy PPE you will need to look for the European Standard codes or the equivalent for your part of the world.  As an individual in England and Wales you could seek PPE from our primary pharmacy organisation.  I was recently informed that a pack of 50 IIR face masks costs £30 and checking their website you can save by buying online.

If you are a company or an organisation that needs to by PPE items in bulk, get in touch with a list of items that interest you, mentioning the quantities, and I will return to you with a quote.  If you like the quote I could forward you to a reliable organisation that can supply you with your PPE needs, whether you are within the UK or abroad.  Please notice a quotation form here.

If you are the employee of an organisation that needs PPE, you could share this webpage with a decision maker within your Human Resources department, for them to find the best person to make contact.

Ending note

Face coverings play a role in the prevention and control of COVID19 but their ability to be preventative to viruses is limited to certain conditions only; information about the perfect working conditions of face coverings will also help prevent and control the virus.  Since face coverings have abilities which vary, information which makes clear that different types of face covering offer varying levels of protection will also help to prevent and control the virus.  While the public may be skeptical about information regarding the virus, the lowering of death rates and transmission rates reflects that the public has generally been co-operative with the guidelines for preventing and controlling its spread.

Special Note

In order to produce this writing a substantial amount of reading and research was completed by Nina Bai, a Web Writer for the University of California, San Francisco.

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