Hi, Doctor Rob here, your biosafety advisor. Let’s learn about masks. Today, you’ll learn how wearing a face mask helps protect you from getting infected, or infecting others, by creating a barrier against harmful pathogens. First, you need to understand that your face is the most vulnerable area for pathogens to enter your body. More specifically, your eyes, nose and mouth. So, to prevent pathogen entry, you should cover those areas by wearing some type of protection – hence the mask.

It’s like raising a shield against arrows to protect yourself. In addition to protecting you, a mask also protects others. It blocks both incoming and outgoing pathogen transmission.

Did you know, that the most common way you get infected is through your mouth and nose. The mouth leading to the gastrointestinal tract (these are the swallowed pathogens) and the mouth and nose leading to the respiratory tract (these are the inhaled pathogens). Face masks block both the nose and mouth, therefore making them a great form of protection against pathogen entry into the body.

Did you know, that there are basically two categories of face masks. Those that do NOT filter out microscopic airborne pathogens and those that do. The non-filtering masks are the most common, as they are simple, cheap, and can create a good barrier against most non-airborne pathogens found in respiratory droplets. Examples are the cloth masks, surgical masks, bandanas, gaiters, dust masks, and even face shields. These masks are made to block the nose and mouth from incoming and outgoing respiratory droplets of pathogens. However, these masks will NOT protect you against small particles, like viruses, gases, or vapors that are in the air you breathe, because these small particles pass right through the mask material.

Now, the second category of face mask (the air-purifying respirators), filters the air you breathe, removing most small airborne pathogens and particles, in addition to blocking the large droplets. Examples are the N95 mask (also known as a filtering facepiece respirator), painter’s mask (or half-face respirators), full face respirator (which covers the eyes, nose and mouth), all the way up to a Powered Air Purifying Respirator (or PAPR). The effectiveness of these masks varies, depending upon the type of respirator you’re wearing and its fit. For example, a N95 mask, under ideal conditions, will filter out 95% of microscopic airborne pathogens and particles.

No matter which category of mask you choose to wear, make sure it fits to your face as tightly as possible, leaving no gaps, so that most of the incoming and outgoing infectious pathogens are blocked or filtered by the mask. This is of course mandatory for respirators, otherwise the air you inhale will go around the mask unfiltered, and you will breathe in the harmful pathogens. For example, if you have facial hair, such as a beard, a respirator just cannot fit tightly enough to your face and will lose filtering capability.

So, consider when you should wear a mask and what category of mask you need. Typically, non-filtering masks are the right choice when you’re exposed to infectious droplets (like talking to someone in close proximity). It’s unnecessary to wear them when you are alone (like in your car, or hiking outside). Filtering face masks (respirators) are more expensive and only needed if you know infectious aerosols (such as a virus) or small particles (such as smoke) are present in the air that you could inhale.

Whichever mask you wear, be sure to wash your hands after removing it, as it may be contaminated. Many face masks, like the surgical mask, are designed to be single use and should be disposed of properly. Reusable face masks, like a painter’s mask, should be disinfected before reuse. You can clean a reusable face mask by wiping the surfaces with a suitable disinfectant based upon the respirator material and manufacturer’s instructions.

So, to recap, remember that the face is the most important part of the body to protect from pathogens. Masks are an excellent form of protection as they create a barrier against harmful pathogen transmission (both incoming and outgoing). Chose the right category of mask and wear it when necessary. Make sure your mask fits tightly, wash your hands after removing it, and dispose or disinfect the mask properly.

That’s the basics on masks, if you would like to know more, check out our advanced lessons. Please mask up out there, so you can – be safe and biosafe.