Experts are divided on the use of a face mask by the public.
You may wonder, Do I need to wear a mask? If so, when should I wear it? And what kind of mask, and how to wear it properly?
Clearly, the purpose of a mask is to prevent the virus from being transmitted either from yourself or to yourself. To varying degrees, all face masks will provide two-way protection.
When an infected person talks forcefully, coughs or sneezes, they will propel virus laden droplets into the air. These droplets are relatively heavy and drop to the ground within 1 to 2 meters. If these droplets strike a person’s face, the mask should stop virus laden water droplets from passing through.
A person can be infected with the coronavirus and not show any signs of disease (that is, no cough, fever or difficulty breathing) and still pass on the virus. This can occur early in a person who later develops symptoms, or the person carrying the virus may never get sick.
To be safe, you should assume that anyone that you are meeting might be carrying the virus or if you have not had strict isolation, you might be carrying the virus yourself. If activities such as grocery shopping put you less than 2 m from other people, a mask can prevent you from either receiving the virus or passing it on.
There are three categories of masks with varying filtering abilities: “homemade” masks, surgical masks, and N95 masks. The most efficient is the N95 and the least efficient is the homemade mask. As there has been a shortage of surgical and N95 and masks, the advice was save these masks for health care workers. Fortunately, the availability of masks is now improving.
All but homemade masks have 3 to 4 non-woven layers, each of which has a specific function. The middle layer is a fine filtration material, usually made of polypropylene with an electrical charge that catches the smallest droplets – down to 0.3 micro m. Homemade masks use fine mesh washable cloth.
Due to the limited availability of masks you may not have much choice in which mask to use. If you have a workshop you may already have N95 masks as they are the standard for dust protection. Clearly due to their heavier construction and tight fit to your face the N95 provides the ultimate protection, however for most encounters a surgical mask provides a similar a level of protection. Homemade masks are less efficient.
Improper mask wearing wastes its value. and may increase your risk of infection. Once exposed, the entire outer surface must be treated as if contaminated. Treat it as though it is dripping with virus particles. Wash or sanitize your hands before you put it on and position it to cover your nose mouth and chin. Leave your mask alone. Do not fiddle with it and do not touch the outer surface. When you are finished with your mask, carefully take it off by handling only the straps and immediately wash or sanitize your hands. If you plan to reuse it, put it into a small cardboard box. After 24 hours or so any virus on the mask will likely have degenerated, and you can then reuse it, considering that it is virus-free.
Surgical masks and N95 masks are designed for single use. However, in a time of mask shortage, the question of mask reuse is important. Due to its robust construction the N95 lends itself to wearing many times. This has been standard practice in industrial settings, where it is often reused many times. With its lighter construction the surgical mask can be reused , however it is more likely to physically deteriorate, especially if it gets wet from heavy breathing. A used mask in good condition is likely as effective as a new mask. Recently some health care workers have been practicing careful mask reuse.
When in doubt, Wear a mask.