Currently, the masks used in hospitals are medical surgical masks. They appear thin and comfortable to wear, yet they consist of three layers: an outer waterproof layer, a filtration layer, and a comfort layer. In addition, they comply with the YY 0469-2004 standard for “Technical Requirements for Medical Surgical Masks.” The outermost blue layer is waterproof, preventing blood and saliva from penetrating the mask. The innermost comfort layer is white and provides moisture‑wicking properties. Do not wear the mask inside out.
Medical surgical masks are typically head‑mounted, meaning they have four loose straps at the corners that secure them around the neck and head. A metal strip is embedded in the upper edge of the mask; after donning, it can be molded to conform to the shape of the nose and face, ensuring a snug fit. Medical masks offer strong protection against bacteria and viruses. In everyday life, they help prevent the spread of infectious diseases such as influenza and respiratory illnesses, and they also reduce the risk of patients transmitting pathogens to others. For fine particulate matter with a diameter of 0.3 µm, the penetration rate of medical surgical masks can reach 18.3%, corresponding to a filtration efficiency of approximately 81%. For particles measuring 5 µm in diameter, the filtration efficiency rises to about 90%, while the bacterial filtration efficiency remains no lower than 95%. Thanks to their excellent water‑repellent properties, these masks provide effective protection against bodily fluids and saliva.

Disposable medical nursing masks, also known as medical protective masks, comply with GB 19083-2003 “Technical Requirements for Medical Protective Masks.” The mask consists of three layers: an inner layer, a middle layer, and an outer layer. The inner layer is typically made of ordinary sanitary gauze or nonwoven fabric, usually white; the middle layer is a fine polypropylene meltblown material; and the outer layer is either nonwoven fabric or an ultra-thin layer. The polypropylene meltblown layer is generally light blue. Additionally, ensure that the mask is not worn inside out. This highly efficient medical protective mask exhibits excellent hydrophobicity and breathability, providing significant filtration against tiny viral aerosols and harmful fine particulates. It delivers overall good filtration performance, uses non‑toxic and harmless materials, and offers comfortable wear. Its filtration efficiency for fine dust particles is no less than 95%. Dimensional standards are also specified: for rectangular masks, the central portion measures at least 17 cm in length and 17 cm in width after expansion; for cup‑shaped masks, the transverse diameter is no less than 14 cm, and the longitudinal diameter is no less than 14 cm. Medical protective masks must not have exhalation valves. Ordinary medical masks that meet relevant registered product standards (YZB) and possess the lowest level of protection can only block saliva and oral secretions. They may be used in general medical settings for single‑use hygiene purposes or for routine ward‑level sanitation activities such as cleaning, liquid dispensing, and bed maintenance, or to prevent or shield against particles other than pathogenic microorganisms (e.g., pollen). However, their filtration efficiency for particles and bacteria falls short of the standards required for medical masks and medical protective masks. For aerosols with a particle size of 0.3 μm, they achieve only about 20%–25% protection, and their filtration efficiency for particles and bacteria does not meet current requirements. Consequently, these masks cannot effectively prevent pathogens from entering the respiratory tract, are unsuitable for clinical invasive procedures, fail to adequately protect against particles, bacteria, and viruses, and are limited to serving as a mechanical barrier against dust particles or aerosols.