Are the masks can be reusable? how to reuse N95 mask

When the new corona virus just happened, many people couldn’t buy masks, and they were out of stock online and offline. Masks should not be wasted. Some of the used masks are still in the sun for the next time. Can used masks be used in the sun? Can used masks be disinfected in the sun? N95instock brings relevant introduction.

Can the used mask still be used in the sun?

Whether the used mask can be used in the sun depends on the specific situation. If the used mask is clean, it can still be used after being exposed to the sun, the radiation and temperature kills virus after 30 minutes. If the mask has been used for a long time, it has been damaged and cannot be used after being exposed to the sun.

It is suitable for the disinfection of all masks. The ultraviolet rays and temperature generated by sunlight can fully disinfect the masks. When exposed to the sun, it should be noted that the masks are best placed in a clean environment, otherwise the masks are easy to get dust inside and outside, and the effect will be reduced.

Professional devices can clean masks carefully.

Can masks be reused after cleaning / disinfecting?

It’s  not recommended if not professional. In real life, no matter after “steaming and boiling” or after using alcohol / ultraviolet disinfection mask, the effect of reuse is greatly reduced.

The following content is from an interview with Professor Jin Xiangyu, deputy director of the industrial textiles Engineering Center of the Ministry of education and professor of the Department of nonwoven materials and engineering of Donghua University. He once presided over and completed the project of “research and development of anti SARS virus protective textiles” against the SARS epidemic.

Truth 1: “Steamed / boiled” will damage the mask structure

Whether N95 or medical masks, they achieve the effect of “anti-virus”, which depends on the “filter layer” adsorption of masks.

The filter layer of the mask is mainly composed of polypropylene melt blown microfiber, which often needs special treatment to carry a small amount of charge, so as to effectively absorb various particles in the air.

Once the mask is “boiled with steam water”, the structure of the filter layer material (polypropylene melt blown microfiber) is damaged under high temperature, and the protection effect is reduced; at the same time, the water will make the charge in the filter layer disappear, resulting in a significant decrease in the filtering effect, so the mask can no longer achieve good protection.


Truth 2: “75% alcohol disinfection and drying” will accelerate mask failure

On the one hand, the external surfaces of medical surgical masks and N95 masks have been treated with “water repellent treatment”, and alcohol, water, blood, saliva, etc. are difficult to penetrate. The purpose is to strengthen the protection of doctors and prevent cross infection caused by liquid jet in contact with patients.

Therefore, it is difficult to apply and spray alcohol on the surface to disinfect the inner part of the medical mask.

On the other hand, alcohol will also damage the waterproof structure of the outer layer of the mask, because the surface tension of alcohol is very different from that of water. The absorption of water (blood, saliva) by the mask material treated with alcohol will increase, which will accelerate the failure of the filter layer of the mask.


What to do if the mask is not enough

In principle, medical surgical masks cannot be cleaned, heated or disinfected. The methods of cleaning and disinfecting will usually cause the deformation of the mask or damage the filter screen, resulting in the degradation of the protective performance of the mask. The same is true for N95 respirators.

For the use of N95 respirators, CDC issued a document, indicating that in special circumstances (such as insufficient supply of respirators, etc.), it can “extend the use period” and “limited reuse” under strict specifications.

“Extended use period” refers to the extension of the use time of the mask, which is not taken down after each wearing, to contact different patients; “limited repeated use” refers to a certain number of times of repeated use under certain conditions.

If the manufacturer clearly states the number of times that the mask can be reused, it shall be subject to the manufacturer’s statement; if the manufacturer does not state that the mask is in short supply at present, if there is no fever or catarrh (runny nose, sneezing, nasal congestion, etc.), it can be reused, but it should also be noted that the number of times/days of repetition should not exceed 5 or 6.