|
Inward Leakage of Air into Face MasksSurgical mask material is fairly good for trapping viruses, but surgical masks as normally worn by themselves are not very effective at protecting you because they are not sealed. The main reason surgical masks fail to protect people is air leakage around the mask, whereby viruses can just easily go around the mask and into your nose and mouth. The amount of air going around a mask is known as "total inward leakage (TIL)" in scientific research.
That is a very big difference -- surgical mask material allowed just 3% to 7% of 100nm particles being breathed, but as normally worn without any external face seal, the air going around the mask resulted in a total inward leakage of around 25% to 35% of 100nm particles inhaled for normal breathing. There are lower percentages for heavier breathing, such as engaging in activity which causes you to breathe harder, probably because stronger breathing sucks the mask to make a better seal, but it's still a very bad seal. If you have a mask using certified N95 or N99 rated material, but it does not seal your face completely, and allows 25% total inward leakage, then that's like having an N75 or N70 mask. In the experiment above, basically, they put a skin-like material onto an advanced manikin headform (sorry, I don't have any photos of their manikin), then they tested particles starting at a size of 20 nm, comparing the air outside to what was breathed inside the mask. Basically, no matter how highly the materials are rated, certified, or perform, they won't protect you well if the mask is not sealed around your face to eliminate inward leakage of air.
I have tried many masks over the years, including respirators which have strong elastic bands. Many of them are uncomfortable. What I've focused on is making sealed masks comfortable. After a lot of prototypes and experimentation, I've come up with the Cross Strap Spongy Face Mask Sealer. It works best with surgical masks and soft N95 masks. Actually, I wear both -- a surgical mask inside of an N95, and thirdly with the Cross Strap Spongy face mask sealer on top of both. After the face mask sealer is attached, I take the ear loops of the other masks out from around my ears, because they are no longer necessary, and the straps around the back of the head are much more comfortable. It is very comfortable for me. I work and forget I have it on. However, I'm accustomed to wearing face masks, so it might take some time for others. A loose mask may be more comfortable, but if you are trying to protect yourself and others from pathogens, then you should be realistic and not rationalize what you may desire. The data above is real. Some doctors seal their surgical masks by putting tape around the mask to seal it to their face. That seems like it would be uncomfortable to wear and maybe painful to remove. An external mask may be more comfortable. Because surgical masks and N95 masks are in short supply during a pandemic, it is suggested you add a facial tissue between your face and the mask which absorbs moisture from your mouth and nose, and change the facial tissue frequently, which can greatly extend the usability of the high value face mask. However, if you don't have access to surgical masks or N95 masks, then you will need to choose an effective material. Please read our page on face mask filtering of viruses.
For a directory of pages on this website, please see our SiteMap, where you might find some more things of interest.
You may contact us via our contact page.
|
Menu: Site Map
|
||||||||||||||
