Domestic can not detect the quality of anti-mite masks

“Will medical masks prevent caries? Is it necessary to wear them at ordinary times?” On March 26, at the opening day of the medical device inspection agency organized by the General Administration of Food and Drug Administration of the People's Republic of China, many participants took this question and ran With the inspection of masks, they entered the Laboratory of Materials Testing of the Beijing Medical Device Inspection Institute (hereinafter referred to as the Beifang Institute) in batches.

Although the size of the laboratory is not large, the reputation is not small. During the fight against SARS in 2003, the Beifang Institute completed the task of drafting three mandatory national standards for medical protective clothing, medical protective masks, and regular absorbent gauze masks in just six days. Medical protective equipment testing laboratory.

Heading out from the crowd, the reporter watched a medical mask filter efficiency test experiment.

"What is the use of medical masks?" Before the experiment officially started, visitors could not help but ask questions.

“ According to performance characteristics and scope of application, medical masks include general medical, medical surgical and medical protection 3 categories, performance evaluation indicators are different.” Yue Weihua, director of the material inspection laboratory of the Beibei Institute, holds the highest level of medical protective masks For example, it can filter particles in the air, blocking droplets, blood, body fluids, secretions, etc., and has a significant filtering effect on micro-virus aerosols or harmful dust. Key performance indicators include non-oil particle filtration efficiency (PFE) and Adhesion.

“Can you prevent it?” The voice of the reply just dropped off, and other visitors quickly asked.

“From the filter media, medical masks are mainly aimed at the filtration of non-oily particulate matter, because the medical environment basically has no oily pollutants.” Yue Weihua explained that according to the standards set by the American Respiratory Protection Association, the medical mask filter grade is divided into N, R For example, R-level mask filters are effective for both oily and non-oily particulate matter, and N-grade filter media filter non-oily particulates.霾 consists of a mixture of solid particles, dust, and microbes that contain both oily and non-oily particles. While medical masks mainly block non-oily particles, there is basically no way to “parry” oily particles.

"Medical masks are only non-oily, like car exhaust, road construction asphalt and other oily substances are not to be prevented." The former director of the Department of Infectious Diseases at the Beijing Anzhen Hospital, the site of the participating activities, and the national medical device review expert Li Yuanchun also agreed The above point of view.

During the conversation, the experimenter Liu Simin picked up a mask and placed it on an automatic filter material testing machine. The 2% sodium chloride solution was atomized into 0.3 micron aerosol particles through a special device to simulate non-oily particles in the air. Then, at a predetermined gas flow rate, the aerosol particles are passed through the mask and the filtration efficiency of the mask is obtained by comparing the number of particles before and after the filtration: 0.722%.

"100% minus this value is the filtering efficiency, and the filtering efficiency of the mask can be calculated to be over 99%." Liu Simin pointed at the machine and explained that simply by passing the aerosol particles through the mask and detecting how many particles were blocked by the mask. . If you block more than 90% of the particles, then the mask is N90; if you block more than 95%, it is N95.

According to the degree of protection, from low to high, medical masks are mainly divided into three types: N95, N99 and N999. The higher the numerical value, the better the filtration efficiency and the relatively thicker filter media used in products. PFE mainly evaluates the masking and filtration efficiency of non-oily particles in the air. The national standard specifies that the protective efficiency of medical protective masks is ≥95% for non-oily particles.

According to experts, at present, in the mask test method, either oil contaminants are used for evaluation, or non-oil aerosols are used for evaluation. There is currently no contaminant capable of simulating cesium for experimental evaluation. Do the so-called anti-mite mask quality testing because there are no specific national or industry standards for civil masks.

At the event, a person in the supervision department who did not wish to be identified told reporters that anti-fog and smog masks were different from medical masks and did not belong to the category of medical devices. As a medical mask used in the medical institution environment, a product registration certificate needs to be issued, and a registration form is followed to indicate the product performance index and application scope. If the manufacturer claims to be a medical device, the registration number can be queried from the relevant channel to identify the authenticity. In addition, the medical mask will also approve the scope of application, beyond the scope of application for description, is exaggerated propaganda, is an illegal act.

From the practical use point of view, as haze weather worsens and continues, medical masks of the N95 or higher level are highly sought after. Manufacturers are also using this to promote publicity and market products are mixed. Experts believe that choosing masks should not be a one-sided pursuit of filtration efficiency. Long-term misuse of “out-of-mouth” masks, such as N- or R-grade filter masks for specific environments, may leave health risks. Li Yuanchun and other industry insiders suggested that relevant state departments should issue product standards and regulate the market according to the conditions of pollutants in the fog.

“Safety-producing protective or medical protective masks are used under specific circumstances. (Anti-mite) can also choose to have a particularly high level of protection, but certainly people are not comfortable, the weather is getting hotter, and outdoor activities can be difficult to breathe.” Yue Weihua suggested choosing a purchase based on personal physical condition and weather conditions. If the haze is not heavy, wear a thin mask; serious pollution, and individuals are very concerned about, you can choose a higher level of filter material.

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