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How to Choose A Face Mask

Are you wanting to buy a face mask but having trouble choosing one?  Or have you already accumulated a wide selection, but are still looking for the best face mask?  Now that there are so many face masks for sale, here is what one should should look for when choosing a fabric face mask.

In the USA prior to March 2020, mask wearing was a custom primarily reserved for healthcare workers.  Surgeons wear masks regularly during procedures for source control.  Now the CDC recommends that everyone wear a mask.  When the CDC put out their recommendation, they said that any layered piece of cloth will do.  If universal masking is to work, everyone must have access to a mask regardless of financial or social status. Whether you buy a mask for sale online or you choose to sew your own, any face covering will reduce the transmission of respiratory droplets compared to no face covering.  But are some masks better than others?  What makes a good face mask?   

Layers

mask layers

The WHO currently recommends that fabric (non-medical) masks be made of a variety of materials including non-woven and woven fabrics.  Woven fabrics alone tend to have lower filtration rates due their mechanical structure, because weaving the fibers naturally leaves a small gap at the intersection in between each crossing fiber.  When 3MD Masks sent our samples of masks with filters to be studied at Nelson Laboratories, the cloth mask with 2 layers of woven cotton had the lowest result at 61% viral filtration efficiency (VFE).  Other studies have found that even tripling the woven layers do not result in significant improvements in viral filtration efficiency.  (For those who already have fabric masks made only of woven materials, we do not wish to discourage continued wear -- 61% filtration is significantly better than no filtration.)  We found that when we added a nonwoven component, such as a light weight low density felt, we achieved significantly more viral filtration efficiency at 81%.  A high density felt, namely our 5 micron filtering polyester felt, achieved the best filtration results at 93.6%. 

Materials

While 100% cotton has been widely recommended, we have found a blend of polyester and cotton fabric to offer the best combination of comfort and moisture wicking.  Pure cotton tends to retain moisture, so that with extended wear the material will accumulate sweat and respiratory droplets, further reducing filtration capacity and encouraging bacterial growth.  Polyester is commonly used in athletic wear because of its quick drying capabilities, but tends to be more irritating to sensitive skin especially when wearing on the face.  We have found a blend of polyester and cotton to be the best of both worlds, in that it is fast drying while still soft and comfortable.  All the materials for our masks are sourced in the USA, and all of our masks are made in Los Angeles.

Some masks on the market advertise "antimicrobial properties", typically in the form of infusion of nanoparticles of heavy metals such as silver or copper into the fibers. We have shied away from these, since heavy metal toxicity can cause long term health consequences. These materials remain largely unstudied in terms of their long term effects on the respiratory system, and therefore should be used with caution per FDA guidelines.  While these "antimicrobial" masks may help prevent the accumulation of bacteria, simply washing your mask daily will do the same.  3MD Masks are completely free of antimicrobial chemicals or heavy metals. 

Breathability

In order for a mask to be useful, they must be comfortable enough for people to keep them on at all times when exposure risk is high.  That means that they cannot reduce air flow below a certain rate.  You can create a mask with 4 or 5 layers of cloth that could provide efficient filtration, however the subsequent increase in air resistance would make it untenable for extended wear unless the materials are extremely thin.  This is why 3MD has chosen to use the optimal number of 3 layers of cloth, two woven and one nonwoven, for our fabric face mask.  Naturally, however, "the better a mask blocks respiratory droplets, the harder it is to breathe through,” according to this NY Times article, and "shopping for a cloth face mask is an exercise in compromises.”  Medical masks have the advantage of using much thinner spunbound nonwoven fabrics, and can maintain their breathability with more layers, as is the case with the Perfetta Ultra 4-layered disposable medical mask. 

Reusability

While healthcare workers, persons over age 65, and people who exhibit symptoms of infection should wear medical masks, the WHO recommends that people who are in lower risk categories wear reusable fabric masks to alleviate the potential shortage of medical masks.  Many masks on the market come with disposable filters that cannot be washed or reused because they will disintegrate with contact to water.  Polyester is a highly durable material that has long been used in clothing manufacturing, and polyester felt likewise tolerates washing well.  When we tested our 5 micron polyester felt filter mask after 920 minutes of machine washing in warm water with a high efficiency washer, it showed durable filtration at 91.7%.  We currently do not know of other masks on the market that have washable reusable filters that will tolerate machine washing.  

Seal and fit

3MD Pro Masks Seal and Fit

In order for a mask to function well, either to protect the wearer or those around them, it must fit well and create a tight seal around the nose, cheeks, and chin.  Any gaps will allow air to travel in the path of least resistance.  If your glasses are fogging with your mask, that is an indicator that the seal is incomplete.  This is why we chose to incorporate a strong yet pliable dual wire nose piece in our masks, to create a complete seal that would prevent glasses from fogging. 

Our pleated design fits a wide variety of face sizes, from pre-teens ages 11 and up, all the way up to large adult sized faces while maintaining the ability to seal around the sides and chin.  This is because with a pleat, any extra material will accordion and fold into itself, maintaining a seal at the edges with different sizes and while the wearer is moving their jaw to speak. The majority of other masks available on the market have chosen a rounded front design (also called the HK mask or Olsen mask), which needs to be properly sized in order to fit well.  When the rounded mask design is too small or too large, it will create gaps at the nose or chin, or it will shift as the person is talking.  If your mask is shifting around or poorly fitted to your face, you will be more likely to be frequently adjusting your mask and touching your face.  Appropriate sizing to create a good seal and fit is essential.  

Masks with filters that are removable PM 2.5 inserts  have the disadvantage of creating gaps between the outer cloth shell and the filter.  More air will escape and travel through the cloth rather than the filter, since this is the path of least resistance.  Studies have shown that masks with separate filter inserts tend to do more poorly clinically than masks that have full-coverage filters.  We have chosen to create our mask with a full-coverage filter that is completely sewn-in in order to avoid any gaps between the filter and the fabric.

It is also important to note that masks with filters that contain the one-way air valve should be avoided.  These are typically seen with construction or pollution masks in order to increase comfort and breathability for the wearer.  However they are not indicated in medical settings because they do not allow for source control, as the one-way valve will allow the wearer’s breathing to escape unfiltered.

Comfort

If you are someone like me who needs to wear their mask for 8 hours a day or more, you want a design that is both breathable and comfortable.  While many people prefer ear loops for ease of use, I personally have found some ear loop masks to be uncomfortable with extended wear due to ear fatigue.  This is why we designed our Pro Mask with elastic head straps that wrap around the head, creating a tight seal that relieves the potential for ear fatigue with longer wear times.  Our Community Masks now come with soft knit adjustable ear loops that can be custom fit to each individual, so that the ear loops are not tugging excessively or too loose with different sized faces.  

Aesthetics

Aesthetic appearance is last on our list because it does not contribute to functionality, however, we acknowledge that stylish masks may be first on some other people’s lists and a good motivator to get the public to wear masks.  If influencers like GQ Magazine and Vogue can make it stylish for people to get on the bandwagon of mask wearing, then this is a tremendous contribution to alleviating a public health crisis.  If we incorporate style and fashion, mask wearing can be a more pleasant experience.  Mix and match with different outfits.  Have a different mask for each day of the week (I know I do).  Using different designs can make it enjoyable for kids to wear masks as well.  Visit our article on finding the right kids masks for more more how these features apply to our kids mask specifically.

From where we started in March of 2020, when masks were in severe shortage, we have come to a much better place now where there is such an abundance of masks for sale that people may not know which mask to choose.  If you are having trouble choosing the best face mask, that is a good problem to have.  3MD Masks has tried to keep all of these important aspects in mind when designing our mask, as frequent mask wearers ourselves even prior to the pandemic.  Regardless of what mask you choose, it is comforting to know that you truly can't go wrong:  any face mask is better than none.



References:

WHO Mask Recommendation PDF  WHO-2019-nCov-IPC_Masks-2020.4-eng%20(1).pdf

 

1 comment

  • Well written and definitely NOT “dumbed down”. A bit long and I would leave out most personal references. Fact dissemination should be short and to the point. I read it because I know the source (you)? Because of all the info you shared, it seems better suited to an infomercial. You could contact a tv station and offer to share some really important tips on choosing and wearing a mask.

    Judy

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