Nowadays, masks are very scarce, especially masks used by first-line medical personnel such as medical protection and N95. In the case of insufficient supply, can we recycle the masks, can we disinfect the masks? Let’s take a look at the science.
For the spread on the Internet, the used masks are steamed in a pot, boiled in water, baked under an ultraviolet lamp, sprayed with alcohol to disinfect and then dried, etc. Reusable coup, Donghua University nonwoven materials and engineering Professor Jin Xiangyu said in an interview with the Science and Technology Daily that whether it is N95 or medical surgical masks, their means of achieving “antivirus” relies on the “filter layer” to adsorb and block microparticles (aerosols) such as viruses, and the filter layer is mainly composed of Made of polypropylene meltblown microfibers.
According to the design requirements, the mask must achieve a good barrier effect while ensuring comfortable ventilation. Its inhalation resistance to medical masks generally cannot exceed 343.2 Pascals (Pa), and the inhalation resistance of daily protective masks is less than 135 Pascals ( Pa).
So 75% ethanol can effectively inactivate the virus, can you spray the used masks with alcohol for disinfection, and then dry it for reuse? This is also not possible. The external surfaces of medical surgical masks and medical N95 masks have passed the “water repellent” Treatment “, alcohol, water, blood, saliva, etc. are difficult to penetrate, the purpose is to strengthen the protection of the doctor to prevent cross-infection caused by liquid spray in contact with the patient.
So is there any way to achieve the disinfection and reuse of masks? The disinfection method adopted in the production process of masks is ethylene oxide gas disinfection, which cannot be achieved by ordinary families. In addition, the mask continuously absorbs the water vapor exhaled by the human body during use, which gradually causes the charge loss of the filter layer and the absorption capacity to decrease. Even if it is disinfected and dried, it cannot be recovered, and it does not provide good protection after use. Under the current epidemic conditions, disinfection and reuse of disposable anti-virus masks should not be advocated.
Although medical surgical masks and medical N95 masks are “disposable”, from the designer’s perspective, unless they go to hospitals, large supermarkets or contact with high-risk places such as suspected patients, ordinary people do not need to use a protective mask to throw It can be used two or three times to reduce the consumption of mask resources.
Finally, a little knowledge of science. The reason why the outer layer of medical surgical mask is blue is on the one hand to alleviate the visual fatigue of doctors at work. The white coat + white mask will be more “dazzling” under the light, which is not conducive to the doctor’s long working hours. On the other hand, the blue surface is treated with water repellent, and different colors are also reminding the user that this is facing outward.
Post time: May-14-2020