Viruses are the smallest particles among the particles we can come into contact with daily. We are familiar with PM2.5, which refers to particles with a particle size of 2.5 microns and below, while the size of the virus ranges from 0.02 to 0.3 microns. Is the virus so small, isn't it very dangerous?
This is a common misunderstanding. It is believed that the mask is a sieve, particles smaller than the sieve hole can pass through, and particles larger than the sieve hole are blocked outside. In fact, N95 masks can effectively block large particles and the smallest particles.
The mask is a multi-layer composite structure. The N95/KN95 mask is composed of the innermost and outermost non-woven fabric layer, the middle electrostatic layer and the meltblown non-woven fabric layer. The medical surgical mask is composed of the non-woven fabric layer and the meltblown non-woven fabric layer. Cloth layer. In addition to supporting the mask, the non-woven fabric layer also serves as a part of the screen, and particles with a large particle size will be blocked by them. Meltblown non-woven fabric has a superfine fiber structure, has good filterability, and can intercept medium-sized particles. The electrostatic layer plays the role of electrostatic adsorption, especially small particles are light and will be adsorbed.
The larger the particles, the better the filtering effect, the smaller the particles, the better the adsorption effect, and the medium-sized particles are the most likely to slip through the network. According to a large number of experiments, this particle size range is between 0.2 and 0.8 microns. Therefore, in GB2626-2006 "Respiratory Protective Equipment—Self-priming Filter Type Anti-Particulate Respirator", the detection of leakage requires that the particle size be between 0.02 microns and 2 microns, and the median is 0.3 and 0.6 microns.
Some N95 masks have breathing valves, can we use them?
The breathing valve opens briefly when exhaling, which may cause microorganisms in the mask wearer to enter the environment, or microorganisms in the environment may adhere to the breathing valve and be sucked into the wearer's body. Therefore, although the anti-particulate masks and medical anti-particulate masks used to prevent haze and dust follow the unified standard, it is best to choose the style without breathing valve for virus protection.
From the anti-microbial perspective, the best choice is a compliant medical protective mask (N95/KN95 mask) without breathing valve.
Although medical protective masks with a high level of protection have better protective effects, because of the high level of filter material, good adhesion, and higher respiratory resistance, wearing them for a long time will increase the respiratory burden and cause breathing difficulties and other discomforts.
In the standard YY0469-2011 for medical surgical masks, there are also clear requirements for bacterial filtration efficiency and particle filtration efficiency. Although it cannot effectively block aerosols, it can effectively block the spread of droplets, which is sufficient as a daily protection.
Compliant products will clearly print the corresponding standard number on the packaging. The standard used for N95 is NIOSH, the standard used for KN95 masks is GB2626-2006, the standard used for medical surgical masks is YY0469-2011, and the standard used for medical protective masks is GB 19083-2010, just look at the standard words on the package when purchasing.
The above information is provided by ear loop face mask manufacturer.
