Birth and development of masks
The original intention of the mask was not to be used as a mask. In 1861, Pasteur discovered the presence of germs in the air, which could lead to infection of surgical wounds. So at the end of the 19th century, doctors and nurses began to cover their mouths and noses with gauze. Since then, the prototype of the mask has been improved for many times, and gradually becomes the current appearance. In 1918, when the Spanish pandemic was raging, masks came out of the hospital and became a common spare part of the public.
Mask to deal with haze
N95, popular in 'extraordinary period'
During the SARS period in 2003, a N95 medical protective mask, which looks like a gas mask, became a favorite in the market. N95 respirator is one of nine kinds of particle respirators certified by NIOSH (National Institute of occupational safety and health). 'n' means particles that are not suitable for oiliness (cooking fumes are oiliness particles, while droplets produced by people talking or coughing are not oiliness); '95' means that under the detection conditions specified in NIOSH standard, the filtration efficiency reaches 95%. This is the lowest level of filtration efficiency of occupational particulate respirators in the United States. N95 is not a specific product name. As long as the product meets N95 standard and passes NIOSH review, it can be called "N95 mask". NIOSH certification is for the product as a whole, not only for filter materials. Qualified products must be filled with NIOSH N95. The separate standard N95 does not indicate that it is a NIOSH certified product. (Note: n represents non oil particles, and R and P represent oil particles. Non oil particles include coal dust, cement dust, acid mist, welding fume, microorganism, etc.; oil particles include oil mist, oil fume, coke oven fume, etc. )
At present, it is believed that the biggest threat to human health in the atmosphere is the inhalable particles (PM10) with a diameter of less than 10 microns, especially the pulmonary particles (PM2.5) with a diameter of less than 2.5 microns. For these tiny particles, the filtering effect of N95 is worthy of affirmation. In the production standard of N95, the test sample for particulate matter is sodium chloride aerosol with a diameter of 0.1-0.5 μ M. the filtration rate of qualified N95 mask for such aerosol should be more than 95%. If we wear N95 or similar dust masks correctly, even if the air quality index (AQI) reports heavy pollution, we may feel a little bit relieved when we go out.
But according to previous reports, some doctors do not recommend that ordinary people wear this kind of mask: 'theoretically, the more airtight the protective material of the mask, the better the effect of blocking particles. Conversely, the more airtight the mask is, the more difficult it is to breathe. If it is not worn well, it may cause dizziness due to lack of oxygen. Wearing N95, a professional protective mask, is easy to cause dyspnea, especially for patients with cardiovascular diseases. '
What is Kn90 mask?
According to gb2626-2006 standard for respiratory protective equipment in China, dust masks are divided into kn and KP according to their performance. Kn is only suitable for filtering non oil particles, and KP is suitable for filtering oil and non oil particles. Kn90 respirator is a kind of respirator with 90% capture capacity for particles less than 2.5 microns. It is reported that Kn90 mask is more suitable for ordinary people than N95 mask.
At present, there is also a kind of mask called PM2.5 on the market, which sounds more professional. There are four spare filter elements in the mask. When using, the filter element can be placed in the interlayer of the mask. After using for a period of time, the filter element can be replaced with a new one.
Correct wearing method
When wearing the protective mask, it should be ensured to fit the face and keep the mask closed to play a good filtering function. After wearing, breath in and breath out tests shall be carried out to confirm that there is no air leakage. The respirator can be reused, but it should be replaced if any part of the respirator is damaged, broken, lost or the resistance increases when breathing. When the mask is removed, it should wait until the inside is dry and then fold it in half to prevent the breath moisture from breeding bacteria. Dust masks shall not be washed with water and shall be discarded after being eliminated.
There are many kinds of masks. Please carefully choose the masks produced by regular manufacturers according to the different situations of different regions and personal physical conditions (the masks are not clean and are more terrible than haze, because the goods are sold on the ground). )