Speaking of N95 masks for preventing smog and dust, let us first understand smog and PM2.5. Does smog=PM2.5? The main components of haze are sulfur dioxide, nitrogen oxides and inhalable particulate matter. Among them, the inhalable particulate matter is what we often call PM (particulatematter). What we often call PM2.5 is pollutant particles less than or equal to 2.5 microns in diameter.
What is the harm of PM2.5? Both are inhalable particulate matter, PM50 and PM10 can only reach our nasal cavity and throat respectively, and will be further advanced by the ciliated tissue. PM2.5 and particles smaller than PM2.5 can directly reach the alveoli and enter the entire blood circulatory system. Imagine a bunch of foreign objects, which are unsanitary by themselves, enter our body directly and circulate in the body. Not only can they directly harm our respiratory system and cardiovascular system, but they are also easy to attach toxic and harmful substances into the human body, which significantly increase the probability of causing cancer, teratogenesis, and mutagenesis. Therefore, it is necessary to choose a N95 mask to prevent smog and dust.
Search "N95 masks for anti-smog and dust" on Taobao. The prices of hundreds of varieties vary. Here we must first explain how dust masks combat PM2.5. Visually speaking, PM2.5 is small, but if we can cover the mouth and nose with a dense mesh, the mesh is smaller than 2.5 microns, then PM2.5 will not be isolated from the body? The "N95 mask anti-smog" we want is a super effective filter. Therefore, the key to the function of a mask is its physical filtering mechanism. It is quite unreliable to say that a certain filter element of dust mask can absorb PM2.5 or can eliminate PM2.5 by chemical means. The key point depends on the material of the anti-smog mask, and only professionally tested materials can filter PM2.5.
Can a haze mask made of cotton prevent PM2.5?
A cotton mask with sufficient layers can filter a considerable amount of dust and bacteria. However, urban air can inhale particulates and fine particles, and the filtration rate of cotton masks is less than 30%. The principle of this kind of fiber mask is a mechanical barrier. Through this layer of mechanical barrier, large particles can be blocked, but particles with a diameter of less than 5 microns cannot be blocked.
Can medical masks prevent PM2.5?
The disposable surgical mask used by surgeons is made of non-woven fabric and is divided into three layers. The outer layer has an anti-droplet design, the middle layer is filtered, and the inner layer absorbs moisture. This kind of mask is mainly to protect doctors from droplets and splashes, and its particle filtration rate is only greater than 30%. The important thing is that the edge of this type of mask does not fit the shape of the face and can only serve as a general shield.
What are activated carbon masks used for? Is it better than non-activated carbon masks in terms of particle protection performance?
Adding a thin layer of activated carbon or other gas-absorbing materials on the particulate protective mask can reduce some low-concentration gas with unpleasant smell, that is, reduce the peculiar smell. Such as: the smell of putrefactive substances (mainly organic substances). When the concentration of odorous gas is so high that it is harmful to your health, you need to use a gas mask.
Activated carbon only increases the effect of reducing certain peculiar smells. In terms of the performance of protecting particles, there is no difference with or without carbon. Activated carbon masks that can reduce odors do not increase the protection of particles.
What is it that people often say that N95 masks are anti-smog and dust-proof?
N95 masks have become the darling of the market since the SARS period. N95 is not a specific product name, it is a classification of masks in the US standard, that is, in the US NIOSH standard, "the efficiency of filtering non-oily particles is more than 95%", and it is reviewed by NIOSH (National Institute of Occupational Safety and Health) A type of mask.
Generally speaking, the higher the filtration efficiency, the better the protection effect, but at the same time the greater the breathing resistance. Therefore, N95 is a good balance of protection and comfort, so it has become a choice for most people.
Even the N95 masks of the same brand have different standards in different countries. For example, 3M's 9001 and 9002 are models produced by 3M in China. They are not sold in the US market and implement the national standard GB2626-2006; while the same is 3M's 9210, it implements the N95 standard of NIOSH in the United States. Therefore, when purchasing, pay attention to the instructions on the packaging of the anti-haze mask to determine which anti-haze mask standard is made of.
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