The Welfie Guide To Masks: Wear One. The End.
Masks have been heavily on my mind since March. It was then that we started to see a decline in the quantity and quality of masks available to frontline health care workers in hospitals, Emergency Rooms, and nursing homes.
I practice as a hospitalist, that is an Internal Medicine doctor that specializes in ‘in-patient’ hospital care. I care for people admitted to the hospital. So, no - not George Clooney in ER (that’s Brandon) and not McDreamy, McSteamy or any McDoc really on Grey’s Anatomy. I am an ‘in-house’ doc.. well... like House. But with much less drama and abusive tendencies.
Here is another way to put it. If you are wondering which doctors are primarily taking care of COVID-19 patients. The short of it is (1st) Emergency Room Physicians (2nd) Hospitalists (more on that shortly) and (3rd) Intensive Care Unit Docs. This list is not exhaustive - Anesthesiologists, Pulmonologists, Infectious Disease, Neurologists, and Cardiologists are just SOME of the list of doctors that are called to the frontlines to care for COVID-19 patients.
And we aren’t forgetting the respiratory techs, nurses, and countless other frontline healthcare workers that are part of the fabric of care in America’s hospitals. Thank you to each one of you.
But I want to take a second and talk about Hospitalists. And, not myself. If you’ve been watching my story, then you know I am not deep in the fray of COVID-19 patients out of an abundance of caution for my recently pregnant wife, now postpartum, and my newborn son. As a hospitalist, I have watched my colleagues step up, and strap-up more types of masks then I would’ve thought existed.
But not only have my peers and I been wearing these masks. But many have stepped into the role of sourcing and securing them.
Whether you’re a doctor or not. You may soon, if you haven’t already, found yourself in this position of getting masks for your family, friends, school, business, and community. So, to help you do so this, we have put together The Welfie Guide to Masks
Before continuing. The above image is NOT to scale. It does not represent a numerical difference between the masks i.e. “N-95 are 10x as good as a cloth mask”. Below we will highlight the key numbers and metrics you DO need to be aware of, and, the science supporting this ordering of respirators, masks, and face coverings.
Should you feel differently, great, let us know why and provide supporting materials. We are here to teach and learn. If there is a common type of mask you feel that we missed. Please point it out. Otherwise, read. share and wear your mask.
PREPARE yourself for a return to school, work, and play by learning the data behind masks.
PREVENT the spread of infection by knowing why you should wear your mask.
PROTECT yourself, and your community by getting the right mask, for you.
How are Air purifying systems rated?
There are a few key government agencies you should know about when it comes to the safety of health equipment
NIOSH - National Institute for Occupational Safety and Health (part of the CDC)
OSHA - The Occupational Safety and Health Administration (part of the US Department of Labor)
FDA - Food and Drug Administration (part of the Department of Health and Human Services
Some of the following stats, metrics, and facts will be sourced from these leading institutions.
Some terms to know, from OSHA:
“Assigned Protection Factor (APF) means the workplace level of respiratory protection that a respirator or class of respirators is expected to provide to employees when the employer implements a continuing, effective respiratory protection program…”
“Maximum Use Concentration (MUC) means the maximum atmospheric concentration of a hazardous substance from which an employee can be expected to be protected when wearing a respirator, and is determined by the assigned protection factor of the respirator or class of respirators and the exposure limit of the hazardous substance. The MUC usually can be determined mathematically by multiplying the assigned protection factor specified for a respirator by the permissible exposure limit (PEL), short-term exposure limit, ceiling limit, peak limit, or any other exposure limit used for the hazardous substance
A very important point. APF is dependant on the MUC, which depends on the Permissible Exposure Limit (PEL). The PEL is the amount of exposure that is allowed, permissible, as decided upon by a government body. For example, lets take Chlorine, which has a “PEL of 0.5 ppm… with a 15-minute short-term exposure limit of 1 ppm…” Where ‘ppm’ means 'Parts per Million. For most infectious diseases, Tuberculosis for example, and COVID-19, there is no PEL. So while the APF is still a valuable number to gauge the quality and performance of a respiratory mask. It cannot be totally applied to COVID-19.
All that being said, when it comes to COVID-19
You want a mask with a HIGH APF.
You want an environment with a low MUC.
Your job, places, and spacing will determine your exposure to COVID-19.
AIR PURIFYING SYSTEMS
PERSONAL AIR PURIFYING RESPIRATOR (PAPR)
PAPRs are positive air pressure systems that help prevent air-borne particles from entering your respiratory system. The basic premise behind a PAPR is that purified air is “blown” into a hood / covering surrounding your head. This creates an area of increased pressure around your face, nose, and mouth. Air, water, anything really, flows from an area of high pressure to one of low pressure. So the high-pressure air in the hood flows out to the low-pressure air in the room. Flow can only happen in one direction. So airborne particles in the room, have little to no chance of getting into the PAPR and into your body.
A brief aside, since we are talking about pressure flow. One of the reasons that health care workers, leaders, and executives are so concerned about the level of COVID-19 cases and hospitalizations is the fact that there are not enough NEGATIVE pressure rooms. Above, I described a positive pressure environment that is created in the hood of a PAPR. In the hospital, patients with air-borne respiratory illnesses are placed in NEGATIVE pressure rooms. This is to prevent the flow of infectious respiratory particles from flowing out of the room into the hallway and other areas of the hospital. By having the pressure of a patient’s room be below that of the hallway. Air flows from the hallway (cleaner, non-infectious) into the room. There are not enough negative pressure rooms in the Hospital for an infux of COVID-19 cases. So if we see too many cases of COVID-19 we do not have the safest rooms to put these patients in. This increases the risk of COVID-19 spreading to healthcare workers, other patients, and their visitors. This is one reason it is so important that we wear masks, flatten the curve and prevent overwhelming the healthcare system
If you are looking to learn more about PAPRs, here are a few resources
ELASTOMETRIC FACE MASK (FULL/HALF)
I have seen a few of these around my hospital, and jealously eyed those who have them. While some may think this is “overkill” there is some anecdotal evidence that these types of masks have quite a great effect on preventing infection from airborne particles.
One of my close friends, a Gastroenterologist in the DMV area, has been wearing one of these. Commonly seen in construction and laboratory settings these types of filters feature cartridges that can be exchanged. This is great if you find yourself in various work environments with differing needs for filtration. Depending on the cartridge purchased, these masks can achieve a high rate of particulate filtration, for example, the P100 cartridges used in Honeywell North 7700 masks can filter out 99.97% of particles. Meanwhile, N-95 masks, which are more widely known, filter out 95% of particulate matter when tested with particles of approximately 0.3 microns.
For more on use of Elastomeric Masks, see below:
HALF-MASK (N-95 / K-N95)
The N-95 mask has rapidly become one of the most sought after pieces of personal protective equipment. Prior to COVID-19, N-95s have been commonplace in the hospital setting. Every year I am “Fit Tested” for an N-95 mask to prevent Tuberculosis infection. So I have been wearing them for years, and relying on them to keep myself safe.
N-95 Masks have their name for a reason.
NIOSH identifies 3 classes of particulate filters for respiratory masks.
N - not resistant to Oil
R - Resistant to Oil
P - Oil Proof
So that takes care of the letter, how about the number, ninety-five. When tested in what NIOSH calls, “the worst-case scenario” these masks are able to filter out 95% of 0.3-micron particles.
The Worst-Case Scenario, as defined by the CDC/NIOSH:
Air flow that simulates a high work rate (85 +4 liters per minute for single filters, 42.5 +2 liters per minute through each filter for paired filters)
The most penetrating aerosol size (approximately 0.3 micrometer)
Charge-neutralized particles
The most filter-degrading test aerosol for R- and P-series filters
Measurement of instantaneous (not average) penetration
High total filter loading (up to 200 mg for N- and R-series filters, and continued loading until there is no further decrease in efficiency for P filters)
There are several types of N-95 masks.
The type most commonly seen in the healthcare setting do not have a valve
While the type commonly seen in non healthcare settings do have a valve.
The difference?
Well as Atul Gwande aptly puts it, in the context of COVID-19, these N-95s are “more comfortable but more sinister…” as while they filter out 95% of particles upon inhalation, they do not provide that filtration with exhalation. “I protect me; I expose you”. he writes in this New Yorker Article
In fact. I think this is a great way to break down the masks and face covers that we wear. Note that the question marks below DO NOT mean there is zero protection. But if we select “protection” as the high bar of less than 5% of particulates being inhaled while wearing a mask. Then yes, that protection is questionable.
https://www.cdc.gov/niosh/docs/96-101/default.html
But what you should know and remember about N-95 masks is summed up nicely here:
“N95 masks are designed to remove more than 95% of all particles that are at least 0.3 microns (µm) in diameter. In fact, measurements of the particle filtration efficiency of N95 masks show that they are capable of filtering ≈99.8% of particles with a diameter of ≈0.1 μm (Rengasamy et al., 2017). SARS-CoV-2 is an enveloped virus ≈0.1 μm in diameter, so N95 masks are capable of filtering most free virions” - see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224694/
SURGICAL MASK
The surgical mask has been quite ubiquitous in hospitals and outside of hospitals. You’ve probably been seeing them here and there for years.
This may seem a little late, but now would probably be a good time to break down, just how masks, of almost any kind help protect us. The following is taken from an article posted on a CDC blog.
Inertial impaction: With this mechanism, particles having too much inertia due to size or mass cannot follow the airstream as it is diverted around a filter fiber. This mechanism is responsible for collecting larger particles.
Interception: As particles pass close to a filter fiber, they may be intercepted by the fiber. Again, this mechanism is responsible for collecting larger particles.
Diffusion: Small particles are constantly bombarded by air molecules, which causes them to deviate from the airstream and come into contact with a filter fiber. This mechanism is responsible for collecting smaller particles.
Electrostatic attraction: Oppositely charged particles are attracted to a charged fiber. This collection mechanism does not favor a certain particle size.
I point these out to highlight a very important and key point about medical grade masks. Electrostatic attraction is a key component of how well your mask can capture particles without increasing resistance, or making it harder to breathe.
In some fibrous filters constructed from charged fibers, an additional mechanism of electrostatic attraction also operates. This mechanism aids in the collection of both larger and smaller particle sizes. This latter mechanism is very important to filtering facepiece respirator filters that meet the stringent NIOSH filter efficiency and breathing resistance requirements because it enhances particle collection without increasing breathing resistance.
Surgical masks primarily rely on being a physical barrier to exhaled particles. Given their design, and those of most cloth masks as well, there is a varying degree to which a seal is formed on the wearers face. It is because of this that when a wearer inhales a breath, there is a chance that air in the room can enter around the mask.
However, layers of medical-grade surgical masks carry an electrostatic charge that traps particles in the air. This is a key differentiator from cloth masks and is a consideration if you are choosing between a cloth mask and a surgical mask.
So…. Why wear a mask?
A few key points. The worldwide spread of COVID-19 has been aided by what is called “asymptomatic spread”, which means people are able to carry the novel coronavirus without getting COVID-19. Let me pause and state this another way. The ‘Novel Coronavirus’ is the name of the virus, you can have the virus, and pass it on, without having the diagnosis of COVID-19. COVID-19 is the syndrome (a group of symptoms) or diagnosis of carrying the novel coronavirus made by a laboratory test. This is perhaps an unnecessary point but important to understand.
People who carry the novel coronavirus and do not show symptoms are able to pass the virus on. Masks help the spread of the novel coronavirus, regardless of whether you have symptoms or the diagnosis of COVID-19.
My mom is a pediatrician. She has yet to meet her first grandchild. And with the US and Canadian border currently ‘closed’ to all non-essential travel. We suspect, as a pediatrician, she will have a small window to travel, if a window does open up. Here is why…
Every year, as students return to school, the health care system, from pediatricians to hospitalists see a similar pattern. Schools open in late August or early September. About two weeks after that there is a spike in cases of respiratory illness (colds) in children that begins to appear in pediatric offices. About two weeks after that, usually around the beginning of October. We start to see more and more causes of Acute Respiratory Illness (Colds) in the doctor's office, emergency room, and hospital. And then, on the heels of these “common colds”, which can be caused by rhinovirus, adenovirus and even ‘regular’ coronavirus, we often see the influenza virus, or “The Flu”. Last year, the 2019 flu season was a doozy. As a hospitalist, “Flu Season” is like the holiday/Xmas season in retail. It is an all hand on deck response to increased flow in the healthcare system. I worry that this system will crumble under the weight of COVID-19 and The Flu.
This is why wearing a mask will be important. Crucially. If we all wear a mask we have the chance to not only stop the spread of the novel coronavirus, and COVID-19 cases. But also decrease the spread and cases of the “common cold” and “the flu”. This will be an amazing thing. Not only for the healthcare system to be able to respond to what will inevitably be a busy fall. BUT this is actually perhaps one of the best things that can happen to the economy.
Here is why. In a world without COVID. Every fall, kids get sick and miss school, so parents have to miss work. Every fall, parents get sick and miss work. Absenteeism from school and work costs the US economy billions. In a world without COVID “Flu costs the U.S. approximately $10.4 billion…”, according to the CDC. So, let's just think about masks from the perspective of seasonal flu. If wearing a mask, can significantly decrease the number of flu cases, and thus flu-associated absenteeism from school and work, then wearing masks can save the US economy millions, if not billions of dollars. In an economy reeling from the effects of COVID-19, masks will not only save lives but could perhaps save billions of dollars, increase productivity, and decrease absenteeism.
If you are wondering how well surgical masks do at decreasing the spread of coronavirus, rhinovirs and influenza, see this study published in nature. The table below shows a stark drop in virus detection when a surgical mask is worn for both coronavirus and influenza virus.
CLOTH MASKS & FACE COVERINGS
I have to admit, I was a little peeved when I heard that the government was recommending “bandanas” to healthcare workers as COVID-19 cases were climbing. Was this better than nothing? Sure. But in a healthcare setting, this is wholeheartedly unacceptable.
Bandanas, cloth masks, t-shirts, scarves, and a multitude of DIY face coverings are becoming a regular part of life. But how well do these work? And what is the best combination of “off the shelf” materials to put together for a face mask?
We are not totally in the dark in answering this question and we do have data and science to guide us and give some insight into how effective some of these masks are. In 2013 Davies et al. published a study, which, in their own words “examined homemade masks as an alternative to commercial face masks.” This study asked the question about how well homemade masks would work in a viral pandemic. A few things to note, they used a bacterial stand-in, less infectious, but about the same size of the influenza virus. And some key takeaway highlights
100% COTTON T-SHIRT - Filtration efficiency of approximately 69%
VACUUM CLEANER BAG - Filtration efficiency of approximately 94%
SURGICAL MASK - Filtration efficiency of approximately 96%
Please note, the test I am referencing here is not the same as that performed to certify N-95s and these numbers should not be compared.
see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7108646/
My favorite DIY face mask is this one, it was handcrafted by a dear friend of mine, actress Erin Cummings. But sentimental value aside, the thing I love about it is the knowledge that this was not just a labor of love, but also supported by science. Studies evaluating cloth masks have shown that materials with a higher density and thread count are better physical barriers than those with lower thread count. Erin chose denim for a good reason, aside from being an all-American fabric and fashionable choice, it has been found to be, alongside canvas, one of the best readily available fabric for homemade masks.
In addition to this, what I love about her design is the pocket. This allows the regular cloth mask to be upgraded with filter material, including surgical masks, and even vacuum bags or furnace filters which have been shown to have great filtering efficiency. IMPORTANT: If choosing a filter be sure to evaluate the material that it is made out of. Some filters not designed for respiratory purposes, like furnace filters, may have fiberglass and other particulates.
To avoid this risk, one thing I’ve been doing to prolong the longevity of my surgical face masks is using them as a filter layer in this homemade mask. This protects the surgical mask from dirt, dust, moisture and adds a few days of usage.
Dr. Yang Wang, an award-winning aerosol researcher took a look at the filtration efficiency of common household items. And compared them to the efficiency of an N-95 mask (empty black square). Bandanas (filled black squares) and scarves (red dots) performed poorly compared to furnace filters (pink circles).
see: https://news.mst.edu/2020/04/environmental-engineers-study-fabrics-materials-for-face-covers/
Given the high filtration efficiency, electrostatic charge, and overall safety and quality assured with surgical masks, they remain the go-to day-to-day choice for me as a filter in cloth masks or solo selection for protection.
PROTECT your self and your community. Be sure to get high quality, certified supplies to keep your self and community members safe.
We’ve covered a lot of ground in this article. But the question remains which mask is right for you. Our general recommendation is as follows.
HEALTHCARE WORKERS - N95s, KN-95s and beyond
FRONTLINE WORKERS - Surgical Masks or Cloth masks with a filter
COMMUNITY MEMBERS - Surgical Masks or Cloth masks with a filter
But masks, like gloves, are not one size fits all. There are many reasons why you might need a mask that should otherwise be “reserved for healthcare workers”. Some things to consider:
Are you at a high risk of exposure to the novel coronavirus?
Are you at high risk of severe illness or even death if you got COVID-19?
Do you, or someone you live with, have a weak or “compromised” immune system?
The answers to these questions may make you consider wearing a more protective face mask. Ultimately, we trust you to do the best thing for you, your family, and your community. Wear a mask and face covering. Practice social distancing. And spread love, not the virus.
Resources you may like
RESOURCES
https://www.welfie.com/blog-1/2020/7/9/8745coeh4sx0dz7ta6u377vyc6hupe
https://www.cdc.gov/niosh/npptl/pdfs/UnderstandDifferenceInfographic-508.pdf
https://www.nytimes.com/article/coronavirus-homemade-mask-material-DIY-face-mask-ppe.html
https://www.cdc.gov/flu/pdf/business/Toolkit_Seasonal_Flu_for_Businesses_and_employers.pdf
https://www.cdc.gov/niosh/npptl/pdfs/UnderstandDifferenceInfographic-508.pdf
https://www.newyorker.com/science/medical-dispatch/amid-the-coronavirus-crisis-a-regimen-for-reentry
https://news.mst.edu/2020/04/environmental-engineers-study-fabrics-materials-for-face-covers/
https://www.nytimes.com/article/coronavirus-homemade-mask-material-DIY-face-mask-ppe.html