1. General medical mask ordinary medical mask is a common gauze mask, which has four layers, eight layers and sixteen layers. It meets the relevant registered product standards (yzb), and generally lacks the filtration efficiency requirements for particles and bacteria, or the filtration efficiency requirements for particles and bacteria are lower than those for medical surgical masks and medical protective masks. The protective effect of ordinary medical masks on pathogenic microorganisms is not exact, so it can be used for primary health care in ordinary environment, or the barrier or protection of particles other than pathogenic microorganisms such as flower powder. 2. The medical surgical mask is suitable for the basic protection of medical personnel or related personnel, as well as the protection to prevent the spread of blood, body fluid and spatter in the process of invasive operation, which meets the technical requirements standard of medical surgical mask (yy0469-2011), and the technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance: 3 Medical protective mask, also known as medical N95 mask, is suitable for medical staff and related staff to protect respiratory infectious diseases transmitted by air, with high protection level; it meets the technical requirements of medical protective mask in gb19083-2010, and the technical indicators include filtration efficiency of non oily particles and airflow resistance. The price of medical masks is cheap, which depends on the ingredients. The price ranges from a few cents to dozens of yuan. The price of general medical masks is 0.5 yuan / piece, that of medical surgical masks is 1-5 yuan / piece, and that of medical protective masks is 18 yuan / piece. In order to avoid the safety of masks, purchase medical masks to pharmacies operating legally, or purchase from manufacturers and agents with health license or medical device registration certificate. The protective mask has the protective performance of surgical mask and particulate matter protective mask. It is used in the hospital. It can filter particles in the air and block droplets, blood, body fluids and secretions. It is also a class II medical device product and must comply with the mandatory standard gb19083-2010. The earlier version of gb19083 was formulated urgently during the outbreak of SARS in 2003, and the old version was revised in 2010. Gb19083 has clear requirements on the filtration efficiency and tightness of masks, which is similar to gb2626-2006. Medical protective masks are also surgical masks, so it is not allowed to set up a breath valve to prevent the droplets generated by the wearer from polluting the surgical wound through the expiratory valve. The blue-green appearance of many medical protective masks is just a habit of the medical industry, The material on the outer surface of the mask can block the body fluid from splashing. In this regard, non-medical particulate matter protective masks are usually not considered。