All masks are disposable and should be worn and then thrown into closed containers
Each type of mask described below is for single use. It means that the masks do not expire, because they must be thrown away immediately after use in closed containers.
How to use it
Incorrect use of masks and respirators can increase, rather than reduce, the risk of transmission of the infection. You must wash your hands before putting them on, after removing them, and you must not touch them in the part in contact with the mouth and nose (also external).
You have to wear it by taking it from the elastic, avoiding touching it. It must cover nose and mouth. When it becomes wet, it must be replaced with a new one and not reused. To remove it, the same rule applies: take it from the elastic by folding it over itself and avoiding touching the front with your hands. Once thrown (in the undifferentiated), it is necessary to wash your hands again.
The duration of use depends on how much humidity is created with breathing (and this in turn depends on the models), they should be changed every 4 hours, or in any case after a "medical procedure", a replacement that is certainly recommended in ideal situations.
Who should wear them
Masks should be worn by coronavirus sufferers and those who care for them, such as health care professionals or the people who care for them. Patients must wear surgical masks, the health care workers or assistants must wear masks FFP2 and FFP3 (see below). Surgical masks can also protect immunosuppressed people who are at risk of contracting diseases and more exposed to infections. The use of surgical masks in red or hotbed areas can be useful if you work closely with unknown people: taxi drivers, employees of offices open to the public, transporters, cashiers.
Masks for the not sick
For healthy people, masks are not indicated. The mask will probably make little difference when walking outdoors and alone.
Using a surgical mask can defend others if we are sick or without symptoms. In any case, we must keep the recommended distance of 1 meter. The masks provide protection by blocking the droplets emitted by sick people. The surgical masks are not made to protect the wearer.
The facial filter masks, certified FFP2, FFP3, are designed to protect the person who wears it from viruses.
For how long can we use it
Surgical masks (and not those for doctors) are "disposable", once used, they should be immediately thrown in the trash.
The respirators or facial filter masks are certified FFP2, FFP3 and after a few hours the filter is exhausted and must be replaced.
The different types
The masks are divided into PPE "Personal Protective Equipment" and DM "Medical Devices" or "Medical masks". PPE on the market, of whatever type or category they are, must bear the CE marking. There are about forty in the field of respiratory protection.
In the specific case, the type of filtering masks required to avoid contagion from Coronavirus (classified as "biological risk"), are regulated by the European standard UNI EN 149. This standard, according to the filtering efficiency, classifies the masks in FFP1, FFP2, FFP3, where FF means Semi Filtering Mask.
FFP1, FFP2 & FFP3
The recommended masks (for those who must protect themselves from the virus, therefore doctors and people in contact with the sick) are of class FFP2 or, better, FFP3 which have a filtering efficiency of 92% and 98% respectively. These masks are "wasted" if used by the infected person. And they are effective only if worn with a precise procedure, precisely for this reason they are not recommended for children or people with beards or glasses, due to the "impossibility of perfect adaptation to the contours of the face.
FFP1 with 78% efficiency are insufficient to protect against the virus, they are also called "dustproof".
The "Medical masks" (so-called "surgical") perform a different function than the PPE. They have the characteristic of not spreading viruses in the air. These masks, other than FFP2 or FFP3, can prevent the patient from spreading the infection, but do not protect it from contagion due to poor adherence to the face. «UNI EN 14683 identifies three types of masks, Type I, Type II and Type IIR, which differ in terms of bacterial filtration efficiency of 95%, 98% and 98% with protection against the penetration of splashes of body fluids. After use, these masks, being potentially contaminated, must be immediately discarded avoiding contact with other parts of the body.
There are also disposable masks with so-called "filters", erroneously called so because they are actually valves that allow more comfortable breathing and reduce heating due to the heat of the breath. But be careful: they are not good for the sick because the valves "throw out" the virus, while protecting the entrance.
P2, P3 and KN95
Finally, there are also masks in elastomers or technopolymers equipped with a replaceable P2 or P3 filter regulated by UNI EN 140 (half masks and quarter mask) and UNI EN 143 (dust filters). The Kn95 filter is slightly lower than the Ffp2. The filtering efficiency of these devices is similar to those of the FFP2 and FFP3, with the advantage of a better seal on the face but with greater discomfort due to the increase in weight.
Finally a clarification:
protecting yourself with a scarf or do-it-yourself masks of non-woven fabric or other material (such as parchment paper, for example) does not guarantee adequate protection and above all it can give a false sense of security that can make us release the guard , for example, on the distance to keep.