I’ve been observing and listening to people for the past several weeks regarding mask attire during this coronavirus outbreak. 

The problem is that there are several factors in determining if or how a mask can protect you and protect those around you: 

The What: The material of the mask.  

The How: The fit, the handling and the care of your mask can help or hurt you.

The When: In what situation you should cover up?

The Who: The healthy? The vulnerable? Everyone? Who should wear one?


The “Why” is another story.  

Different countries and states have slightly different recommendations for their residents to wear masks.  COVID-19 is, of course, a respiratory infectious disease so we should consider the mechanisms of airborne particle transmissions.  

Did you know, when we exhale the small respiratory droplets evaporate in the colder, drier environment (outside our mouths) and form residual particulates called aerosol. These aerosols are less than 10 micrometers (um) in diameter and can travel across rooms depending on ventilation and wind factors.  Recent work has demonstrated that an exhalation, sneeze, and cough are made of a multi-phase turbulent gas (a puff) cloud, trapping the droplets and resisting evaporation for longer periods of time due to its warm, moist atmosphere. So, within the cloud, the particles can transmit much farther. Depending on the person’s physiology, the humidity and temperature of the environment, we are talking about a range up to 23 to 27 feet (7 to 8 m)!   These are significantly larger distances than the recommended 6 ft by the CDC and most countries.  

And the speeds on peak exhalation can reach up to 33 to 100 feet per second (10-30 m/s) 2,3 

We need to consider the “Dynamics” of Emissions when Someone Coughs, Sneezes or even Exhales.  

Refer to the Jama news article cited below. 1 There is a fascinating video demonstrating emission distances of a violent exhalations (sneezes) from healthy individuals showing carrying distances of a range that may surprise you. In this article in JAMA News, Dr. Lydia Bourouiba from MIT says: “Even when maximum containment policies were enforced, the rapid international spread of COVID-19 suggests that using arbitrary droplet size cutoffs may not accurately reflect what actually occurs with respiratory emissions, possibly contributing to the ineffectiveness of some procedures used to limit the spread of respiratory disease.” 1

So, based on these numbers, she is saying our social distancing with or without masks isn’t helping to “flatten this curve” very much at all. 

To Mask, To Distance, or Both?

WHAT Type of Mask? 

The N95Mask. These offer the best protection when fitted and handled properly. They are designed to filter out droplets as small as 0.3 um. For airborne particles to reach deep into the lung alveoli (where coronavirus does its damage), they need to be less than 10um in diameter (aerosol). 4 

We all know the N95’s are in short supply and we are encouraged to save them for medical and front line personnel.  So, the other options could be better than nothing. 

Large droplets (larger than 10um in diameter) are the ones you can see in the air generated by a cough or sneeze. These are usually trapped in the nasopharynx (nose and throat region) and can get as far as the bronchi in the upper lung region. Therefore the following two masks can help block the large droplets.

The Medical Mask. These offer protection from the large droplets and can filter up to 80% of small particles. Keep in mind they do not fit snugly around the face. 

The Homemade Mask. Self-made masks need to be made from dense fabric, multilayered and sized for enough tension to fit snugly behind the ears sufficiently and allow comfortable breathing. Pay attention to the weave and spacing between fabric fibers. Small droplets (<10um) may easily transmit through, however, these masks can offer protection from large droplets.  Make sure your fabric does not contain any harmful chemicals and use a layer of cotton on both sides.  

Limiting exposure to other peoples’ sneezes and coughs by covering your nose and mouth with any type of material – even the lesser effective surgical masks or homemade masks, will at least offer some protection.  

The N95 Mask

HOW to wear it. 

It should fit firmly and snugly over the bridge of your nose and around the mouth. My concern with masks, especially homemade ones is the gapping I see around the sides which invites particle transmission as well as the subconscious tendency for the wearer to keep adjusting it. Touching their faces and the masks increase transmission risk. 

Applying and removing it should be done without touching the exterior surface.  Ideally, it should be stored in a secure container. N95 masks are meant to be disposed of after use, however, due to our shortage, we try to preserve them for multiple-day usage. 

Washing reusable masks, such as homemade ones should be done in very hot water and hung outside in the hot sun to dry or in the dryer.  Remember to wash your hands after handling the mask (and preferably before you touch it). 

This seems like a lot of work, doesn’t it? Wearing a mask can put you at more risk for contamination. It’s quite possible to unconsciously touch your mask, contaminating your hands then touch your face!  I’m just saying do your best and be mindful when handling and wearing a mask. Just as you should be with all other hygiene measures.

WHEN to wear it. 

If any question can stir a debate this one will. Some of you reading this could be asking IF you should wear a mask. I’m not telling you if you should or shouldn’t wear a mask. That’s up to you. But I will share my own insights based on my state’s recommendation and what I do professionally and personally. I suggest checking with your own local guidelines or those of the CDC.  

6 Feet or 23 Feet? I would wear one when in any situation where you are within 6 feet from others. BUT, based on the dynamics of respiratory transmission explained earlier coupled with the fact that we do not know anything about the health and exposure history of the strangers around us, is a minimum 23 ft distance is a safe criterion for mask-wearing? How is this possible when humans are social creatures? 

However, I personally do not wear a mask when I’m out in open spaces such as a quiet mountain trail or walking my dog in the park. I like to inhale fresh air when possible. It’s part of my recommended healthy lifestyle.  I just keep one handy in case I find myself around others outside my family circle.  

I also do believe that herd immunity is a good strategy. But this a whole other topic of discussion.


WHO should wear a mask.  

Your personal health status is a determining factor as well as that of those around you.  

Are you vulnerable to the virus? Should you wear it to protect yourself? Or others? Or both? 

A healthy non-elderly individual (one with no chronic disease, exercises a longstanding healthy lifestyle, who is a non-smoker and has a good track record of overcoming colds and flues quickly) should wear masks when working with or near vulnerable individuals to protect them.  This of course, includes medical personnel. 

Individuals with questionable health status should of course, protect themselves with masks and exercise caution with proper distancing. 

Unless you are in total isolated lockdown, you obviously can’t control who comes within 6 ft of you during an essential errand. You can turn a corner in a grocery aisle and right into the path of a non-masked carrier or active unaware viral individual. How do you know if he or she is a carrier of this or any virus? How do you know if this person is in denial or not diagnosed with a chronic condition or oblivious of their exposure history? And this person ventured out right into your 6-foot range path? We can drive ourselves crazy just thinking about the what if’s.

We do not have complete control and keep in mind, a mask will not give that to you. 

The Maskdemic

The “maskdemic” has heightened the anxiety among those who are fretting about:

A. Not finding a mask OR 
B.  Feeling they are at higher risk of getting the virus if they don’t wear a mask OR  

C. Feeling criticized for not wearing one.  

If you find yourself in any or all of these situations, wrap a scarf or bandana around your face, take your immune supplements and have some comfort in knowing you put a physical barrier across the parts which are vulnerable to large particle transmission. 

The fact remains that there is no conclusive evidence that a mask will make a big difference.  

There are several sides to these arguments but I personally think wearing any mask can’t hurt if you wear it properly and handle it carefully. Nothing is going to fully protect you from any bug or virus. The strategy is to build healthy lifestyle practices and do everything within your power to improve your function so when (not if) you come into contact with the virus, you are in a better position to process it and build those antibodies.  

What are your thoughts? Feel free to comment below.  

I welcome a healthy discussion on the Mask Confusion. 

Dr. Melanie



2. Bourouiba  L, Dehandshoewoercker  E, Bush  JWM.  Violent respiratory events: on coughing and sneezing.  J Fluid Mech. 2014;745:537-563.Google ScholarCrossref 

3 Bourouiba  L.  Images in clinical medicine: a sneeze.  N Engl J Med. 2016;375(8):e15.PubMedGoogle Scholar 

4. https://medium.com/@Cancerwarrior/covid-19-why-we-should-all-wear-masks-there-is-new-scientific-rationale-280e08ceee71 

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