Summary:
After doing extensive research on various face masks, it is clear that there are several misconceptions about them. For one, the typically surgical masks provide no protection against viral constituents for the wearer – rather, these are to protect those around you from any droplets you may exhale. Also, there is no mask that provides complete protection against diseases – not even the highly rated N95 masks. Of the masks available to hospital staff, these are not designed with a pandemic in mind. One major fault of surgical masks is that they do not provide a tight fit around the face. The loosely fit masks that many hospital staff are seen to wear are better than no mask at all – but still not good enough. Droplets are able to enter through the sides of the masks and are not suitable for medical staff who come into contact with patients each day.
Another major fault with current masks is the absence of any ventilation. When worn for prolonged hours, sweat and vapor from exhaling builds up in the masks leading to several disastrous effects. For one, this excess moisture can lead to pressure damage on the skin of the face, leading to skin tears from the friction of the mask. In this situation, it is difficult for medical staff to simply apply bandages since this may make wearing a mask even more uncomfortable. Also, these skin tears invite various infections, and, with the excess moisture, became a breeding ground for bacteria. While less severe, this excess moisture can also fog up spectacles and in general become a nuisance and discomfort. A mask should have proper ventilation with the use of exhausts to prevent these effects.
Existing HVAC filters provide a clever product for repurposing, given their ability to filter small products effectively. It is however advised to only use filters with a MERV rating of at least 12, as well as to ensure that the product does not contain fiberglass. Inhaling fiberglass can cause respiratory irritation along with pulmonary disease. There is also evidence to suggest that the inclusion of activated carbon in charcoal has the potential to aid in filtering against viral and bacterial airborne diseases.
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Design Concepts
Research
Journals:
Active Carbon Respiratory Masks as the Adsorbent of Toxic Gases in Ambient Air
https://www.hindawi.com/journals/jt/2019/5283971/
It has been shown that the use of spun bound, melt blown activated carbon in masks is significantly more effective in absorbing toxic gasses than traditional surgical masks. Activated carbon has a large particle size and large surface area, this makes it especially effective at absorbing larger particles. Typically, activated carbon masks are made by applying the carbon between the spun bound and melt blown layers in a mask. This experiment tested the protection against various toxins, specifically those known to cause respiratory and cardiovascular diseases in the most vulnerable groups – the elderly. The particles researched belonged to the COx, NOx, and SOx groups. However, this article cites research that N95 masks with carbon integrated are much more effective in filtering airborne bacteria and viruses than those without carbon.
The problem with existing masks is that they do not provide any additional layers of protection against especially small particles. The inclusion of carbon provides another defense against not just toxic gasses but also airborne illnesses – bacteria and viruses. This could be a viable option to integrate in a new mask design given that activated carbon is relatively cheap and can be found in most drug stores and general stores.
A Simple Method to prevent spectacle lenses listing up on wearing a face mask
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293317/#__sec1title
According to this article published by the National Institute of Health in the US National Library of Medicine, fogging of glasses when wearing face masks is a large problem for medical staff. The reason this occurs is because the face masks are designed in a way that redirects the exhaled air upward where it will get into contact with the lenses of the wearer’s glasses. This is because there is a mist the forms when the warm water vapor condenses on the cooler surface and forms tiny droplets. These droplets form because of the surface tension between the surface and the water molecules.
One way to prevent this from happening is to wash the spectacle lenses with soapy water. This will form a thin surfactant layer on the glass that will reduce the surface tension between the water and the glass. This effectively forces the water to spread out evenly along the glass creating a very thin layer of water. This is a method used in treated various types of glass. The soapy water should be left to air dry with the excess shaken off. This should however be done immediately before wearing the glasses.
This article provides insight on the causes of the fogging up of glasses. These is pertinent information included in how to improve vision when this happens but does not explicitly mention any different design to the mask. This article does however say that the masks design is at fault, given the way the masks redirect the flow of the wearers exhale. Therefore, a mask should be designed in such a way to redirect the flow of the exhale so that it does not move up to the wearer’s face and causes fogging up of glasses This is a very large concern for many medical staff as well.
Websites:
1. A comparison of Surgical Masks, Surgical N95 Respirators, and Industrial N95 Respirators
https://ohsonline.com/articles/2014/05/01/comparison-respiratory.aspx
Masks serve the primary purpose of protecting the patient rather than the wearer. However, some masks provide the advantage of protecting the wearer against exposure from large particles, microorganisms, bodily fluids. Surgical masks are not however effective against inward leakage of particles and organisms and are typically not designed to cover the nose and mouth tightly. The purpose of an N95 masks to the limit the exposure of the wearer to airborne biological containments but do not completely eliminate this risk. These masks form a tight seal around the wearers face and are fluid and oil resistant.
A mask can be brought to the market after gaining approval by the FDA. However, the FDA itself does not do any testing but rather relies on the test results of the manufacturer. For an N95 masks to be put on the market, it must undergo testing by the NIOSH, which performs independent tests in government laboratories – testing the filter efficiency, degradation, and flow rate.
This article provides insight into the certification and testing of masks. Additionally, it highlights the advantages and disadvantages as well as major differences between traditional surgical masks and N95 masks – which are significant better in defending against biological contaminants. In general, it was found that the purpose of a masks is to protect the patient rather than the wearer. When designing a mask, it is important to keep in mind different flow rates when testing the filtration. Also, important when designing a mask is to keep in mind the fit of the mask to the face. A major problem highlighter in this article is that traditional surgical masks are not designed to be fit to the face. This is what allows particles to enter through the gaps of mask between the face.
2. What’s the Best Material for a Masks?
https://www.nytimes.com/article/coronavirus-homemade-mask-material-DIY-face-mask-ppe.html
Federal officials recommend using any sort of fabric to cover the face. This is only effective in blocking outgoing germs but fails to block ingoing germs. The purpose of these masks is to simply protect everyone in your surroundings rather than the wearer. Scientists had run extensive tests on easy to find and common household filters to determine the best filter that provides the greatest protection against incoming and outgoing germs and bodily fluids. These tests included, vacuum cleaner bags, HEPA furnace filters, high thread count pillowcases and fabrics such as flannels. A good test for filters at home for those without experimental equipment is to do the light test. Simply shine light through the material to see how much passes. This is a method created by anesthesiologist Dr. Scott Se4gal that can provide insight to how dense a fabric and weave are.
It is important to keep in mind that lab studies are typically performed under perfect conditions without the possibility of leaking around the sides of the masks. This continues to be a major fault in most masks. Some materials promoted online may be unsafe to the wearer and in times unbreathable. Pleated fabric is seen to perform very well and has a filtration efficiency of 60-80%. Another test found that HEPA air filters are able to filter out 89-90% of particles. 89% in one layer and 94% with two layers.
When selecting a filter, use one with an allergy reduction filters with MERV ratings of 12 or higher or a microparticle performance rating of 1900 or higher. This filter must be sandwiched between layers of cotton to prevent any particles from the filter from being inhaled. You should use four layers at least of any filtering material to be safe. The filtration increases almost exponentially with the addition of filter layers.
3. How to make a CDC-Approved Cloth Face Mask
https://www.wired.com/story/how-to-make-a-cloth-face-mask/
It is recommended to wear a face mask in addition to social distancing to provide the greatest protection against airborne illnesses. Wearing a cloth mask is especially effective in protecting those around you if you do not yet have noticeable COVID-19 symptoms. The purpose of the mask is not only the prevent bodily fluids from leaving your mouth and nose but also the stop you from touching your face and transmitting other bacteria and diseases from your hands to face. A mask should never be grabbed by the moth area or that which is exposed to your surroundings. It should be removed from the face by the straps. It is not enough to just wear a standard bandana or scarf, there should be multiple layers to tightly cover the face.
According to the U.S. surgeon, when making a mask from cloth, you should fold it over four times. There is an outlined procedure to making your own mask published by the CDC that uses rubber bands/hairbands and cloths. To assembly, take the material, lay it flat and fold it from the bottom to the middle and from the top to the middle. Loop a rubber band or hair tie around each end and leave a few inches of fabric so that each side looks like a candy wrapper. Then fold the excess over the band. Lastly, put a band aid over each ear, and make sure the material fits snuggly over the face. You must make sure there is pressure up against your face to prevent leaking or particles from the sides.
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4. All the different types of face masks, and who should wear them during the corona virus pandemic
https://www.businessinsider.com/types-of-masks-used-for-coronavirus-outbreak-n95-surgical-2020-3
This article compares the various types of masks available as well as those than can be made. The writers focus on how different masks are used for different people, what they are good against, and why they are used. Essentially, premanufacture masks should be left for professionals who need them, but the general public is advised that if they are to leave their house, they should wear a homemade mask such that they’re not taking away masks from those who really need them. This article also highlights that beards should not be worn given that they prevent from a decent seal between the mask and face from forming.
Homemade masks are recommended to be worn by everyone. These can be sewn, cut, or fashioned form a bandana or coffee filter and should be routinely washed. The people who should wear these are people entering crowded areas for a limited time. As for surgical masks, these are worn by surgeons such as not to get germs on the patients. However, they can also protect the wearer from getting sick through their spit but will but help healthy people from acquiring illnesses because of the loose fit. These masks should be worn by already infected people. Only healthcare workers should wear N95 masks and should be able to dispose of them after use. These masks are designed for biohazardous environments and can block out 95% of small airborne particles given that they fit snuggly to the face. Also, interesting to note: The N in N95 means not resistant to oil, and the 95 comes from the 95% capture rate of particles that penetrate the material in the worst conditions.
This article essentially highlights a very important fault in traditional surgical masks: the loose fit. The loose fit as compared to other masks allows particles to enter from the sides of a mask already not designed the defend the wearer from outside particles. The surgical mask should only be worn by already sick people such to not infect others. However, no mask can prevent illness 100%.
5. The Facts About Facemasks
https://health.ny.gov/publications/7224/
Main Idea: Washing face masks.
This article was published by the New York State Department of Health and explains the differences between different masks and preventative measures during outbreaks. The writers highlight that a mask should be worn when going out the prevent spreading disease to those around you.
Taking care of face masks involves the following – laundering, disposing, and not touching. Cloth facemasks can be washed using hot water and disposable face masks can be washed as well but only once before they must be thrown away. Facemasks should not be handled as germs can be spread from your hands to the fabric. Facemasks should also be changed once they get moist. Moisture provides a breeding ground for bacteria, so masks that are worn frequently that have excess moisture should be disposed.
Given the durability of cloth as a face mask, this article provides insight into designing a mask that can be reused multiple times by simply throwing it into a washing machine. Given the lack of face masks in hospitals and those generally available, this would be a major step in maintaining supply.
6. Preventing Skin Damage due to Face Masks
https://www.medicalnewstoday.com/articles/preventing-skin-damage-due-to-face-masks
Main Idea: Face masks cause skin damage.
Face mask respirations are designed to fit snuggly on the face to prevent leakage of biohazards through the sides. This also has the effect of cause damage to the skin in hot environments. This is caused by sweating under the masks which causes friction. This can lead to pressure damage on the nose and cheeks which causes the skin to tear. This also has the potential to cause infections through the skin. It is difficult to dress the wound given that applying gauze or bandages may make the mask difficult to wear or fitting correctly.
This article explains specifically the device related pressure ulcers. This is a large risk for health care workers who are expected to wear these masks for extended periods of time. Since symptoms of corona virus take about fourteen days to appear, the exposure of wounds increases infections of coronavirus in healthcare workers. The CDC suggests that when the wearer of these masks feels friction or rubbing – then they should take the mask of as soon as they safely can. The CDC asks that people do not buy up medical grade masks given the ongoing shortage of protective equipment for healthcare workers.
Given the conditions of the ongoing pandemic and the infection risk that current masks provide, the mask should be designed to release excess moisture such that there is proper ventilation. This should also not compromise the barrier created to prevent viral pathogens from entering the mask. Therefore, there should be a device attached which would allow airflow in and out of the mask but also keep the blocking power of a N95 mask.
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7. Can You Use HVAC Filters in Corona Virus Masks?
https://www.energyvanguard.com/blog/can-you-use-hvac-filters-coronavirus-masks
Main Idea: Parameters for using furnace filters for face masks.
It is highly advisable to wear a face mask when going out because it is typically spread by droplets from coughing or sneezing. Breathing alone can also put droplets in the hair when you only exhale. Larger droplets are capable of spreading viruses and can often float for long periods of time before landing on a surface. These droplets can also be easily breathed in and cause infection. Current medical professions use surgical masks which provide a significant decrease in protection when compared to N95 masks.
A homemade mask has the capability of reducing small droplets from getting out by about 10%. They do an even better job in protection against large droplets which evidence would suggest providing better conditions for corona virus. When making a mask from an air filter, it is important to understand that not all air filters are made from the same material. Generally, the higher the MREV rating, the less likely the manufacturer is to use fiberglass. These filters are typically made from polyester and cotton, you should aim to only use filters with an MERV rating of 12 or higher.
Manufactures of these filters advise people to not breath into them directly and instead use a type of binder or other material to offset the gases and toxic chemicals.
Using cloth is better at filtering out larger droplets, and HVAC filters are good at filtering out smaller droplets. An HVAC filter should not be used along in a mask and should instead be sandwiched between a cloth material to offset the chemicals – and potentially fiberglass – that may be found in the air filter.
8. What You Should Know
https://www.cdc.gov/niosh/npptl/topics/respirators/factsheets/respfact.html
Main Idea: Chemical cartage masks only work if the correct filter is used. Charcoal is not as effective against absorbing viral substances as frequently believed.
9. How Not to Wear a Face Mask
https://www.nytimes.com/2020/04/08/well/live/coronavirus-face-mask-mistakes.html
Main idea: Mask should not be worn below the nose, chin should not be exposed, should not be loose, should cover OVER the nose, never push mask below the chin.
10. The Experts got it Wrong on Face Masks
https://www.spiked-online.com/2020/04/06/the-experts-got-it-wrong-on-face-masks/
Main idea: Current masks are all too easy to be worn correctly. New masks should only be able to be worn a single way. Due to the shortage and increasing demand, scarcity for masks has increased and prices have gone up.