How To Choose Six Kinds Of Common Masks

There are many kinds of masks. How to choose? Zhang Yucheng, Department of disinfection, Institute of infectious disease control and prevention of the Municipal Center for Disease Control and prevention, recently introduced the use of various masks. Jin Xiangyu, Professor of Textile College of Donghua University, also gave an answer to the children's masks needed for returning to school.

Disposable medical mask: daily use. The bacterial filtration efficiency (BFE) of disposable medical masks should be more than 95%, and the ventilation resistance should not be greater than 49pa / cm2. This kind of mask is suitable for ordinary people to use when they are not in contact with patients with fever, cough and other symptoms. It is enough to wear them when they go out or take public transportation.

Medical surgical mask: can be used in hospital. The results showed that the bacterial filtration efficiency (BFE) of medical surgical masks was more than 95%, the pressure difference between the two sides (equivalent to ventilation resistance) was not more than 49pa / cm2, and the particle filtration efficiency (PFE) was more than 30% (non oily particles); the synthetic blood penetration test (2ml synthetic blood, 16.0kpa, inner impermeable) was also required to test whether the mask could be penetrated by splashed blood and sneezing spray. This kind of mask is suitable for hospital environment. It has a distance of more than 3 meters with patients with fever, cough and other symptoms. It is recommended to wear it when going to the hospital or visiting patients.

Medical protective mask: for contact with patients. The medical protective mask can filter most microorganisms, resist the splashing of blood and body fluids to a certain extent, and the outer surface has certain waterproof property and high tightness. The filtration efficiency of the particles is more than 95% (non oily particles), and it has certain surface moisture resistance through a higher standard of synthetic blood penetration test (2ml synthetic blood 10.7kpa, inner impermeable). The protective effect of such masks is better, but the comfort is poor, which will make the user feel the breathing is not smooth. It is generally used when professionals contact with patients with respiratory infectious diseases.

Kn95 mask: suitable for short-term contact with patients. Filter elements of filter type respiratory protective equipment are divided into kn class and KP type according to their filtration performance. For microorganisms, it is enough to recognize kn, and the number "95" refers to the filtration efficiency level. Kn masks only test the filtration efficiency of particulate matter, and do not test the penetration of synthetic blood and surface moisture resistance. Such masks can block the virus in a short time, but can not be used to contact patients who may have splashing or long-term contact with patients. Novel coronavirus pneumonia patients can be used by ordinary people and for short time medical staff. But long time contact with patients can not be used by professionals. In addition, N95 mask is a kind of mask that meets the American Standard. Chinese medical protective masks are one of N95 masks, but not all N95 masks are medical protective masks.

Disposable children's mask: change every day. Do you want to stock up on children's masks in preparation for the start of school? Under normal circumstances, it can be used for one day. Choose the appropriate size of children's masks, including large (L), medium (m) and small (s). When teaching children to wear masks, press the metal strips on both sides of the bridge of the nose with both hands to make the upper end of the mask close to the bridge of the nose, and stretch the mask downward without wrinkles.

Children's masks printed with cartoon patterns and colors may not be safe. The new "civil health mask" stipulates that the fabric directly contacting the mask and the skin shall not be dyed, but this requirement does not apply to the outer layer of the mask. 

Whether the outer layer of the mask is dyed and whether there are various patterns is designed by the enterprise itself. However, the standard does not require it. The pigment for children's mask dyeing should meet the food grade standard, and the mask dyed with chemical raw materials should be worn for a long time It will have a negative impact.