At present, the global epidemic situation of covid-19 is still very serious. Masks, especially protective masks, are one of the important tools to combat the epidemic. This paper puts forward some suggestions on the supervision and development of the disposable mask industry.
The standards for disposable medical masks and medical surgical masks do not have tightness requirements, and the standards for disposable medical masks do not have particle filtration efficiency performance requirements, which cannot ensure full contact between the masks and the wearer's face. External particles, droplets and aerosols can enter the respiratory system such as mouth and nose through the gap. It is suggested that relevant departments such as standard management should improve the standards of the above two protective masks as soon as possible, add performance requirements for tightness and particle filtration efficiency, and improve the protective performance of masks against virus particles with very small particle size.
At present, the main filter material of the mask is polypropylene melt blown cloth, which plays a protective role through gravity sedimentation, interception, inertial collision, diffusion, electrostatic adsorption and so on. Its physical structure can only block the diameter >3 μm for particles less than 3 μm The particles, droplets and aerosols of M mainly depend on electrostatic adsorption. After the polypropylene melt blown cloth material is wet, the static electricity decreases or disappears, and the filtering effect decreases. In winter, especially in northern China, the outdoor temperature is very low, and the water in the exhaled gas forms droplets when it is cold, which makes the polypropylene melt blown cloth damp, reduces the filtration efficiency, greatly reduces the protective performance of the mask, and loses the protective function of small particles such as viruses. Therefore, the mask must be replaced in time after use.
Disposable medical masks and surgical masks are cheap, comfortable and convenient to wear. They are the main types of masks that people use every day, but their performance indicators do not meet the requirements of tightness, and there are major problems in their protective performance, which can not effectively protect against particles such as novel coronavirus. It is recommended that the public only wear disposable medical masks and surgical masks in low-risk areas and places, and wear medical protective masks or kn95 masks in closed, densely populated and high-risk areas and places such as hospitals, high-speed railways, planes, subways, etc; In particular, high-risk staff, such as throat swab collectors, testers, and medical staff in contact with novel coronavirus infected or suspected infected people, should wear medical masks and replace them in time; Children should wear appropriate masks in high-risk places. It is suggested that relevant departments should put forward mandatory requirements for the wearing of masks by the public, clearly stipulate that medical masks or kn95 masks should be worn in areas and places with high risk, and have clear punishment measures for violators to give full play to the epidemic prevention role of masks.
The research of new anti-virus filter material is the key. Tetrafluoroethylene membrane covering material has the advantages of high filtration efficiency, basically no attenuation, and can be reused after washing. Selecting this material to prepare a mask can ensure the filtration efficiency, but because it contains salt particles, the filtration resistance has the risk of rapidly increasing. The unique size effect of nanofibers makes nanofiltration materials have higher porosity than melt blown microfiber non-woven fabrics, and have better permeability while ensuring the filtration effect. It is expected to become an ideal filter material for medical masks in the future.
Novel coronavirus, SARS virus and H1N1 influenza virus all threaten human security through respiratory transmission. At present, the standard performance of masks at home and abroad is not perfect in terms of protection against novel coronavirus, and they cannot be reused. There is no anti-virus mask approved by the drug regulatory department for listing in China. Therefore, there is an urgent need to develop new anti-virus protective masks that can effectively prevent virus transmission and can be reused, and accelerate the research and approval significance of new masks that can be reused and effectively prevent virus transmission.
The outbreak of covid-19 has prompted people to form the habit of wearing masks when going out, especially in crowded public places. Put forward suggestions on the supervision and development of the protective mask industry, in order to provide reference for the further development of disposable mask.