The protective function of a respiratory mask is built on two foundation; first the filter media must be able to let the air in but stop unwanted contamination. Second, a mask has to fit the face of the user tightly so that no air by-pass the filter media and enters the breathing zone directly. Modern technology provides filter media with very high efficiency. However, ensuring a mask fitting a user’s face is not a simple affair. Many users are puzzled if the mask they are wearing really fit their face.
Mask-face-fit testing is the job for an expert, and it require special equipments. There is QUALITATIVE fit test procedure based on subjective senses of the user. Then there is QUANTITATIVE fit test procedures based on objective measurement, comparing the particle counts inside and outside of the mask. Unfortunately, for a typical user, non of these fit test procedure is simple to do. In the US, NIOSH recommended such fit test to be conducted for each user once a year, or when the user’s body weight changed by more than 10%. Fit test can tell if the mask fit the user during the test, but unless the user do this test each time putting on a mask, he or she can can not be sure if the mask really is fitting during use. So far, fit testing procedure are limited to occupational workers. For general public, they don’t have the equipment nor the knowledge to conduct fit test.
In a recent study titled “Respiratory Donning in Post-Hurricane New Orleans” published on the CDC website in May 2007, researchers found only 24% participants demonstrated proper donning. This suggested the protection for at least 76% mask-wearing public would be compromised. Due to the experience of the Post Hurricane clean up, this is a group of user with higher level of knowledge about mask wearing. It is not difficult to imagine, this will be a big challenge for any emergency response when the public need to wear a fitting mask to ensure each other’s safety. CDC has been reluctant to recommend N95 mask for the public use, because for 1 in 4, the N95 mask may provides a fault sense of security while the it is not doing it’s job due to poor fit.
As the designer of TOTOBOBO mask, I try to solve this problem of fit-uncertainty in a different way. Previous fit-test procedure is needed because the user can not tell if a mask is properly sealing his face. Even when a mask looks like it is covering the nose and the mouth, there may be gaps underneath the mask which is difficult to see. The uncertainty is due to the fact that the mask is not transparent. Now what if the mask IS transparent? Then the user will be able to see if it fits right away, fitting or not, very clear and no more uncertainty. This simple method combines with a soft transparent material made mask-face fitting a lot more intuitive and with greater certainty.
With TOTOBOBO solution, it is now possible to perform a face-fit check every time before entering a potentially contaminated area. I think this is more reassuring than relying on a once-a-year fit test.
Posted by chuwasg 
