Some important questions with regards to face masks and COVID-19 in general

Dr Dirk here again, and I want to answer some important questions with regards to face masks and COVID-19 in general.

  • How does a mask that allows for breathability catch germs?
  • Why is natural airflow important?
  • Why is the risk higher to contact COVID-19 in kitchens and toilets?
  • Why are masks with valves wrong to use?
  • Why should a mask seal around your nose and around your mouth?

Kitchen and toilet hygiene are really important to me, in fact, some would call me something of a fanatic with regards to this. People also think I’m crazy to be so adamant about leaving windows and doors open, especially during winter in the southern hemisphere. And, while I’m about it I’ll explain why masks with external filters are not as efficient as they should be.

We recently received this question from a customer:

“A few people here have been asking me if it is breathable, how can it prevent that which is coming in as it must have holes / be porous? “

That is a very good question and it is important to understand the answers.
Viruses are transmitted through micro-droplets, or aerosols. These droplets of liquid contain the virus inside them. The droplets are contained or caught by the fabric of the mask. Viruses are much smaller than these droplets, however, they die quickly if not contained by the droplets.

The air you breathe in and out is made up of Oxygen, Nitrogen and Carbon-dioxide. These are some of the smallest particles you get in the periodic table and pass far easier through fabric than droplets.

One of the CE certification tests that we at eMoyo did was to see whether Staphylococcus, a genus of Gram-positive bacteria, can penetrate through the mask. The bacteria are suspended in micro-droplets and blown through the mask at high velocity. Measurements are then taken of how many of these germs went through and created an infection on a growth medium on the other side of the mask. The eMoyo B~54FE mask filtered out 89% of the bacteria. The typical top range mask that medical doctors use are N95 masks, and they filter out 95% of bacteria or germs.

The other benefit of wearing a mask is that the few germs that may escape are not projectiles moving out of an uncovered mouth. Sneezing and even normal breathing or talking projects droplets out at high speed into the air, often towards innocent bystanders. The mask dampens the speed of the projectile and should germs escape the mask they will stay in close proximity to you, and not spread to other people.

It appears as if nearly 50% of all Corona, or COVID-19, transmissions happen the two days before you start to feel sick or start presenting with symptoms. This is one of the main reasons why you need to wear a mask because you simply do not know if you will get sick in two days time. The mask will then help protect those around you. Of course, a small number of germs can and will leak out, and be suspended in the air around you. This happens no matter what you do or which mask you wear. For this reason, it is of utmost importance to make sure there is natural airflow where you are, at all possible times. For instance, the air must flow in through a window on one side of the room and escape through a window or door on the other side of the room. If there is no natural airflow, these germs will continue to be suspended in micro-droplets in the air, and over time could drift onto someone else and could infect other people.

It is vitally important to wear a mask in communal areas where other people may touch surfaces that your droplets might fall onto. A communal kitchen, for instance, is a risk area. Typically people will take their masks off to taste the food they are preparing or even eat. It is important to keep your mask on in the kitchen at all times because your germ droplets can drop onto the cup that the next person is going to use to drink coffee in.

Other high-risk areas where you could come into contact with airborne germs are toilets and bathrooms. Remember you are sitting in a small area where previously another person sat earlier, sometimes for a very long time checking up on the latest jokes around mask usage by presidents. It is important to wear your mask to ensure your droplets do not drop on the toilet seat or handle, taps, walls and toilet paper. Leave your phone outside the toilet to avoid contaminating the phone, but most importantly, to decrease the time you spend on the toilet. The longer the time you spend, the higher the risk of inhaling that aerosol germ of the previous person. This is also the reason why sound booths for hearing testing is not such a good idea since a patient may spend over 20 minutes in the booth for testing. This is why the booth-free KUDUwave diagnostic audiometer makes so much sense. It is also important to wear the mask to prevent micro-droplets from hanging in the air and possibly infecting the next person walking in. Keep the windows of the toilet wide open, and when you walk out, leave the door open so that a full air replacement can happen through natural air circulation. Preferably wait 10 minutes before entering the same toilet someone else just used.

I have seen social media posts where people laugh at considerate citizens wearing masks while they are driving. First of all, if you sit in an air-conditioned car and are not being active, you forget you have a mask on, but more importantly, you decrease the number of times you touch your mask, furthermore, you decrease the risk of your droplets dropping onto other surfaces inside the car should you be picking up another person to travel with you. Remember, make sure that at least one window in the front and one in the back is slightly open to allow for natural air to flow throughout the car. Ensure the AC is not on recirculate, this point should speak for itself.

This brings me to the point of why masks with these plastic valves on the sides of the mask are not a good idea. Those valves allow for unfiltered air to escape into the air.

The purpose of a mask with valves is only to protect yourself, and not those around you from yourself, and thus misses the reason why it is recommended to wear masks during COVDI-19. I call these masks selfish masks because it is all about protecting yourself and not about protecting those around you. They serve no clinical or antibacterial purpose at all. It is as good as taking a straw and blowing your air towards the face of another person.

Valve mask

The same happens with masks that do not seal around the nose, such as those masks that you see people constantly push up over their nose because it slips down and exposes the nose. That is why the eMoyo mask has a nose plate. It helps to prevent unfiltered air escape past the nose and thus decreases the spread of aerosols. 

Birds Group

Visors are in the same class as masks that allow unfiltered air to be exhaled. Yes, a visor will catch some of your droplets as you speak or cough, but it is obvious that a visor does not protect you at all and certainly not those around you.

A meme is doing the rounds pointing out that one should not pull your mask down around your neck. The mask has your germs on it, and there is nothing wrong with pulling your mask around your neck to drink water or have something to eat. This is blatant and informed false fear-mongering. I have to ask what else will you do with your mask if you do not pull it around your neck – take it off and put it on the table and spread your germs that way? No, keep the mask around your neck. That is why it is better to rather use a mask that ties around your neck instead of a mask that hooks around your ears. It decreases the risk of cross-contamination if you pull the mask down around your neck.

Fake information

The question might come up:  “Not necessarily your own germs only. Someone could have coughed/sneezed on the uncovered/unprotected area of your neck, you pull your mask down”. You have to assume your clothes and all open skin including your uncovered eyes would then also have been in contact with the germs. That means someone else did not wear their mask. The risk of getting a germ from your neck is much less than getting the germs directly into your eyes, as in hundreds of times less. That is exactly why masks are being worn, to protect other people, not yourself. So the droplets of other people should never land on you. If it ever happens then shower immediately and change clothes.

Another post that is shared left, right and centre on Facebook, is that masks will increase the Carbon-dioxide levels in your bloodstream and cause health problems. This is preposterous. As a medical doctor, I sometimes wear a mask for up to 60 hours a week in an operating room. If this testimonial is not enough for you, then I hope the science behind the respiration rate is. The pH level of your blood and carbon-dioxide is the only important factor in this regard. The amount of carbon-dioxide changes the pH in your body. Your body will never allow (except if you are really sick) the pH of your blood to be anything else than 7.4. The moment the pH decreases due to carbon-dioxide, you will automatically breathe faster. And a bit off-topic, this is why all the remedies shared on social media to eat food that are high alkaline, to change your body pH to a higher alkaline level, because cancer cannot survive in an alkaline environment, is pure nonsense. Remember, your blood is naturally alkaline.

Yes, the aim of a mask is to protect the people around me from myself because I can be infected and then transfer my germs to another person. But the mask also protects you from the germs of other people. Masks help to protect yourself. If a person with a valve mask sneezes and the droplets fly onto your mask, then your mask will help to protect you. If your mask isn’t a wet cotton mask, then the droplets will dry out quickly and the germs will die. But, just the same as a mask contains most of your germs as you exhale, so it also filters the air that you inhale, provided that you do not inhale past your nose or through the gaps between your cheek and the mask. And no, good masks do not cause asthma, they may actually help to prevent asthma and are recommended by some asthma authorities to wear when going to a high allergen area.

In the same breath, pun intended, I want to include surgical masks as problem masks. The breathability of typical surgical masks is not that good at all. I make this statement as a medical doctor that has worn surgical masks for decades. The breathability is mainly due to the gaps created by an ill-fitting mask between the mask and your cheek. Unfiltered air escapes here into the air around you through gaps where your thumb can fit into. So it does not matter how well the fabric of these masks filters-air, unfiltered air will escape directly into the air through the gaps on the side of your face. This is why if you cough in an operating theatre you do not turn your back to the patient. If you turn your back to the patient the droplets escape at high speed out through these gaps on the side of your mask, and into the open wound of the patient. This is Rule 101 of surgery. These masks are however not worthless. They do catch some droplet projectiles, but of course, they will not be as effective as a mask that fits well, such as the eMoyo B~54FEmask.

Birds Group

All masks are not created equal. As a medical device manufacturer, we at eMoyo see so many masks that may even increase the risk of transmission of germs. 


  • Please stand far away from people with masks with valves. 
  • If you stand behind someone wearing a surgical mask, stand as far away as possible. 
  • Stand even further away from people with their noses hanging out over their masks like a phallic symbol of proudness. 
  • Do not allow people with inappropriate masks in your businesses or shops. 
  • Make sure windows are open. Yes, it might be cold, but then make a plan, but no cold air blowing through a window is worth the life of a fellow human person.

Ask yourself, “Will the mask I wear help to save a life?”