N type mask
Class N masks are one of nine anti-particulate masks certified by NIOSH (National Institute of Occupational Safety and Health).
"N" means that it is not suitable for oily particles (for example, oil fume produced by cooking is oily particles, and droplets produced by people speaking or coughing are not oily).
The N95 mask is one of nine standards established by NIOSH in 1995. "N" means "not resistant to oil". "95" indicates that the particle concentration in the mask is 95% lower than that of the particles outside the mask when exposed to the specified number of special test particles. The value of 95% is not the average value, but the minimum value, so the average value of actual products is mostly set above 99%.
Other NIOSH certified anti-particulate mask levels also include: N95, N99, N100, R95, R99, R100, P95, P99, P100. These protection levels can cover the protection range of N95, where "R" means suitable for oily or Non-oily particulate matter, if used for the protection of oily particulate matter, the use time does not exceed 8 hours; "P" means suitable for oily or non-oily particulate matter, if used for oily particulate matter, the use time should follow the manufacturer's recommendations. And "99" and "100" refer to the filtration efficiency levels, respectively.
Divided into "N", "R" and "P" according to oil resistance, and divided into "95", "99" and "100" according to the capture rate. "R" means "resistant to oil", "P" means "oil proof", "99" in the capture rate means more than 99%, and "100" means more than 99.7%.
In addition, when the N100, P100, and R100 three-type masks are tested with 0.3 micron particles, the barrier efficiency must be above 99.7%. The N99, P99, and R99 are all filtration rates above 99%, while the N95, P95, and R95 are all filtration rates. Above 95%.
Therefore, N95 masks are tested with 0.3 micron sodium chloride particles, and the blocking rate must be more than 95%. When the wearer's face is tightly tested, ensure that the air can pass in and out through the mask when it is close to the edge of the face. Only those who meet this test will be issued the N95 certification number.
There is a certain gap between the detection methods of domestic protective masks and the detection methods of foreign countries. Generally speaking, protective masks that have passed the certification of existing domestic standards cannot reach the N95 level standard.
Method of choosing
1.Choose the right type of mask
(1) Medical protective masks should be the first choice for medical workers, and ordinary degreasing gauze masks should be the first choice for ordinary citizens to use in daily life. In special occasions, such as visiting doctors and visiting patients, it is better for ordinary citizens to choose medical masks.
(2) The materials used for masks should be free of odors and harmless to the human body, especially the materials in contact with the human face should be non-irritating and allergic.
2. Choose a regular manufacturer
For the prevention of influenza, we usually choose ordinary non-fat gauze masks or medical protective masks, which need to be purchased from various outlets of legally operated medical stores or from manufacturers with health licenses or medical device registration certificates.
3.Select qualified masks
When choosing a mask, it depends on whether there is a trade name on the packaging, whether there is information about the manufacturer or supplier, whether there is a mask certificate or instructions for use. Disposable masks must have a one-time indication, and reusable medical protective masks must be marked with a method of sterilization. In general, ordinary gauze masks must be marked as normal or disinfected.
4. Don't forget to check the appearance when choosing a mask
This is a problem that we tend to ignore when choosing a mask. First of all, we must check whether the packaging of the mask is complete and whether it is damaged. There must be no holes or stains on the surface of the mask. Medical protective masks should not have exhalation valves. For tight arch masks, the lateral diameter is not less than 14cm and the longitudinal diameter is not less than 14cm; the length of the medical protective rectangular mask is not less than 17cm, and the width is not less than 17cm. The number should not be less than 12 layers. In addition, we must remind everyone that if you choose a medical mask, remember to have a nose clip. The nose clip is made of bendable plastic material and the length is not less than 8.5cm.