Due to the lack of uniform standards and specifications, the quality of "anti haze masks" is uneven, and the market competition is chaotic. On April 25, the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and the Standardization Administration of the People's Republic of China issued the national standard Technical Specifications for Daily Protective Masks, which is the first national standard for civil protective masks in China. The standard will be officially implemented on November 1, which clearly stipulates the protective effect of fine particles (PM2.5) and the safety performance of wearing.
"This will change the chaotic phenomenon that China's civil respirator market has no standards to follow and no standards to check, and play a positive role in ensuring the effective regulation of the market and rational guidance of consumption." Li Lingshen, president of the China Industrial Textile Industry Association, who participated in the formulation of the standard, said.
At present, the standards for respirators in China include Respiratory Protection Articles Self priming Filtration Type Anti particle Respirators, Technical Requirements for Medical Protective Masks, and Medical Surgical Masks, but they all belong to labor protection and medical protection standards. The so-called civil anti smog masks on the market have always lacked standards and specifications.
For example, many masks use "filtration efficiency" to express their anti haze performance, and often claim that "the filtration efficiency is more than 90%". Li Lingshen pointed out that the filtering efficiency only refers to the filtering effect of the filter cloth material, which is the core part of the mask, and does not represent the protective effect of the mask, because the mask has the problem of sealing. Even if the filtering effect of the filter cloth can reach 99%, the protective ability of the mask will be greatly reduced if the sealing is not good.
In view of this, the Technical Specification for Daily Protective Respirators uses a comprehensive indicator such as "protective effect" to define the performance of respirators with the intuitive effect of "air quality inhaled after wearing respirators". This can avoid the shortage of current masks that only focus on the filtering effect and ignore the sealing.
"According to the standard, the respirator can reduce the concentration of PM2.5 inhaled to less than 75 micrograms per cubic meter after wearing, so that the air quality in the filtered inhaled body reaches a good level or above, which is qualified." Li Lingshen pointed out.
The air inhaled after wearing the mask should at least reach the "good" level in the air quality standard, but the air outside the mask is very different, which puts forward different requirements for the performance of the mask. Therefore, the standard divides the protection level of respirators into four levels from low to high: Level D, Level C, Level B and Level A, which correspond to the air quality category setting and air pollution in the national air quality standard respectively - Level D is suitable for moderate (PM2.5 concentration ≤ 150 micrograms per cubic meter) and lower pollution, Level C is suitable for severe (PM2.5 concentration ≤ 250 micrograms per cubic meter) and lower pollution, and Level B is suitable for severe pollution (PM2.5 concentration ≤ 350 micrograms per cubic meter), Class A is used when the PM2.5 concentration reaches 500 micrograms per cubic meter.
That is to say, you can check the air pollution before going out in the future, and then choose the mask to wear according to the actual situation. "It is not recommended to wear masks for a long time and beyond the standard." Li Lingshen reminded that the higher the protective effect of masks, the higher the relative respiratory resistance. Wearing masks with high respiratory resistance for a long time will have adverse effects on health.
It is understood that in order to ensure the safety of the public when wearing protective masks, the standard requires that masks should be able to protect the mouth and nose safely and firmly, and there should be no accessible sharp corners and edges. The standard has made detailed provisions on formaldehyde, dyes, microorganisms and other factors that may cause harm to human bodies. It also stipulates that materials that may be harmful to human body shall not be used. Considering the safety of the wearer when walking, the standard stipulates that the field of vision under the mask should not be less than 60 degrees, to avoid affecting the wearer's line of sight due to the high arch design of the mask.
"Generally speaking, the higher the protective performance, the greater the impact on the comfort performance. When people wear masks to inhale, the masks have a certain resistance to the air flow. When the inhalation resistance is too large, people will feel dizzy, chest tightness and other discomfort conditions. Different physical differences will lead to different feelings of comfort." Li Lingshen said that the standard is to maximize the comfort of the wearer on the premise of ensuring the protective effect.
Li Lingshen said that due to the large differences in children's physical characteristics, the accumulation of medical data and experimental data on the impact of respiratory resistance on children's growth needs to be improved, so there is no special provision for masks for children in the standard, but clearly pointed out that the standard "is not applicable to masks for children".