The best masks hold up to 95 percent of harmful particles, but even those you can make on your own can provide the protection you need. Polyester, cotton, paper towel and even a vacuum bag: there are plenty of materials that masks can be made from. The New York Times writes about which of them are the most spectacular.
N95 type mask
The N95 is the most effective mask. Its name says that it traps at least 95% of particles as small as 0.3 micron (by comparison, a human hair is 70 to 100 microns thick). All thanks to polyester and other synthetic fibres that act as a filter. The main thing is to make sure that the mask fits snugly on your face and never reuse it. In addition, it is important to know that N95 masks with breathing relief valves do not protect others from the air you exhale.
Medical 3-ply mask
There are many varieties of disposable medical masks, but none are as effective as the N95. Nevertheless, they filter out 60 to 80% of particles and, when used properly, help prevent the spread of coronavirus by catching droplets when you cough or sneeze. Medical masks consist of several layers of breathable synthetic fabric with pleats that help it expand and fit more snugly over the face.
With the scarcity of masks, many began to make them with their own hands. Depending on the type of fabric and the manufacturing method, a homemade mask can provide a level of protection comparable to its medical counterpart (in any case it is better than nothing). The main thing is to ensure a tight fit to the face. A mask should be made of a material that is dense enough to trap fine particles, but at the same time will not make it difficult to breathe. The mask can be made from cotton, flannel, or even kitchen towels. The less light the fabric lets in, the better it will protect you from the virus.
Homemade mask with filter element
You can also make this kind of mask out of a simple cotton t-shirt, with a pocket for an extra filter. You can use a filter from a coffee machine or a paper towel: the experiment showed that two layers of such towels block from 23 to 33% of particles up to 0.3 micron in size. Some craftsmen even adapt air filters and vacuum bags for this purpose. They too can be effective, but at the same time can be too dense or contain harmful fibres.