I want to introduce a new mask filter that can be cleaned and reused a for a month. In Korea, there was a lot of demand for air filters because of the fine dust. Therefore, people not only used masks but also various filters, including window filters. Several companies have been developing and using nano filters since a few years ago, and began selling Nano filters that can be used in masks. This new nano filter was made by attaching nanofibers with a diameter of 100 to 500 nm to general fibers in a right angle or in a single direction. The nano filter is a very thin, continuous form of fiber, which is fundamentally different from the controversial fine particles which may cause some harm to human body. Since the fiber is formed of fine continuous thread, it does not flow into the human body and is completely harmless. And this filter showed excellent filtering, breathability and multi-use performances.
Existing mask filters such as the ones used in the N95 are made through the melt-blown method and then exposing them to high voltage. In other words, electricity is formed on the surface of the fiber and particles are filtered by static electricity. However, the nano filters have shown to be better at catching particles because they filter through the nano fiber itself rather than through static electricity, meaning it physically catches the particles.
The nano fibers used in nano filters are an average thickness of 190 nanometer, which is around 1/500 of a hair’s thickness. The two pictures below were taken by electron microscopy (SEM) after filtering through 0.3 μm fine dust under the same conditions. As can be seen from the photo, the new nano filter has much more particles caught in the fiber than the older ones.
^ New Nano Filter
The processing of the fine Nano Scale is smaller than the size of viruses, bacteria, and dust, as well as external droplets of saliva, preventing these harmful substances from entering the body when breathing. The nano filter can successfully filter fine materials with a size of 0.7 μm with rate of 94% up to 98%. This can be considered to be high enough to filter out the size of the virus in droplet forms.
The size of the coronavirus itself is 0.1 μm, but when it comes out from people, it comes out in the form of an aerosol of 5 μm or more. And, in general, the cough is sprayed within 2 m and falls, which will then die. That is why it is possible to block the virus through the usage of a mask. Of course, when the virus from someone’s cough evaporates and floats in the air, there is a risk of exposure to the infection, but this possibility is unlikely.
In the case of N95 Mask, it filters about 95% of fine particles of about 1μm, but it is said to filter even fine substances of 0.3μm size. Therefore, it is recommended to use the N95 mask in an environment such as a hospital, but in everyday life, a mask capable of blocking more than 80% of microparticles is sufficient. But since the N95 mask can filter ultra-fine particles, it also become hard to breath in. So, it is not only frustrating and uncomfortable when worn, but can also strain the body of patients with chronic respiratory or heart disease.
One of the biggest advantages of Nano Mask is that it has excellent filter performance and breathability at the same time. Nanofibers are thin once and in addition, the porosity of the nanofibers eliminates discomfort when breathing by reducing the pressure loss that occurs while passing through the filter. Compared with the existing masks for fine dust, the nano filter is said to have a better ventilation of 2.5 times or more. So, if you use a nano filter, you can make a mask that is much more comfortable than other masks, including the N95 Mask.
Since the existing mask blocks dust with electrostatic force, it loses its static force over time or when it comes into contact with water and moisture. Therefore, it is generally recommended to use it only once, and to not wash it as it will cause poor filter performances.
However, nano-filters can be used multiple times, since there is not much deterioration in filter performance due to less deformation of the material even after washing, and since the filtering is done through the actual fiber than static electricity, there is no electricity loss that needs to be worried about after coming contact with moisture. It’s said it can be washed more than 20 times, and if it is soaked in alcohol, it can be sterilized more than 30 times and can be used for up to a month. A new nano filter has a filtering performance of up to 98%, but it maintains a 94% filter efficiency even after 20 washes. This is similar to the performance of N95 Mask.
Therefore, the nano filter-based mask is effective enough to obtain an effect similar to the N95 Mask depending on the material used for the exterior and lining, and is a more breathable mask too. Furthermore, since this washable mask can be used more than 20 times compared to a disposable mask which can be only used once before being discarded, it is not only a cost saving but also a good for the environment by creating less trash. That's why I think this Nano filter is a universally usable, reliable filter.
Nano filter: Reusable/Washable Nano Filter
By Sue Kim