Common masks include: cotton masks, disposable masks (such as surgical masks, surgical masks) and medical protective masks (N95/KN95 masks).
Among them, medical respirators (N95/KN95 masks) and medical surgical masks are medical products prescribed by the state since SARS in 2003, and have the function of preventing the passage of liquids and droplets. If worn correctly, it can effectively prevent droplet-borne diseases. This is our top pick for face masks. They usually consist of multiple layers of non-woven fabrics.
Medical protective masks should comply with China's mandatory GB 19083-2010 standard, with a filtration efficiency of ≥95% (using non-oily particulate test). It must pass a synthetic blood penetration test (to prevent splashing of bodily fluids) and meet microbiological indicators.
The N95 is one of nine respirators certified by the National Institute for Occupational Safety and Health to protect against particulate matter. "N" stands for non-oily particles (cooking fumes are oily particles, while talking or coughing droplets are not), while "95" refers to 95% filtration efficiency under NIOSH standards. Also, the mask fits the wearer's face very well. It filters airborne particles and blocks pollutants such as droplets, blood, body fluids and secretions. It is commonly used personal protective equipment against airborne diseases.
N95 is not a specific product name. Products that meet the N95 standard and are NIOSH approved can be referred to as N95 face masks.
Microorganisms are non-oily particulate matter. In the NIOSH standard classification for particle masks, class N is used to filter non-oily particles. For example, soot from frying is oily particulate matter, whereas droplets from talking or coughing are not.
In China, it is the national standard KN95, which refers to the classification of non-oily particulate masks according to the national standard GB2626-2006. KN grade is suitable for filtering non-oily particles. The digital portion of both countries has the same standard. 95 means filtration efficiency ≥ 95%.
The filtration efficiency test methods of the above three standards are the same, so the filtration efficiency level is consistent.
In addition, there are European standard FFP2 (oil and non-oil particle protection, with virus and bacteria protection, filtration rate is about 94%~95%) and European standard FFP3 (oil and non-oil particle protection, with virus and bacteria protection) protection) protection, the filtration rate is about 99%).
Medical masks are operated in environments where there is a risk of body fluids and blood splashing, such as commonly used masks, blood, contamination of body fluids by body fluids can prevent the wearer from wearing them, filtration efficiency exceeds 95% bacteria, but the filtration efficiency of particulate matter is high and limited, And most of them are rectangular designs, with the function of snugly fitting the face and medical protective masks. Common surgical masks include strap-type and ear-hook types.
Viruses are the smallest particles we come into contact with every day. We are familiar with PM2.5, which refers to particles with a particle size of 2.5 microns or less, while viruses are 0.02 to 0.3 microns in size. The virus is small, isn't it dangerous?
A common misconception is that a mask is a type of sieve that allows particles smaller than the sieve hole to pass through, while particles larger than the sieve hole are blocked. In fact, the most effective range of N95 masks is between the large particles and the smallest particles.
The mask is a multi-layer composite structure. N95/KN95 masks are composed of innermost and outermost non-woven layers, middle electrostatic layers and melt-blown non-woven layers, while medical surgical masks are composed of non-woven layers and melt-blown non-woven fabrics. Floor. In addition to supporting the mask, the nonwoven fabric layer also acts as part of the screen ACTS, which will block large particle size particles. Meltblown nonwovens have ultra-fine fiber structure and good filtration performance, which can intercept medium-sized particles. And the electrostatic layer plays the role of electrostatic adsorption, especially when the very small particles are very light, they will be adsorbed.
The larger the particles, the better the filtering effect; the smaller the particles, the better the adsorption effect; the medium-sized particles are most likely to escape from the net. According to extensive experiments, the particle size range is between 0.2 and 0.8 microns. Therefore, in gb2626-2006 "Respiratory Protective Equipment - Filtering Respirators to Prevent Particulate Matter Self-priming", the detection of leaks requires a particle size between 0.02 microns and 2 microns, with a median of 0.3 microns to 0.6 microns.
