Original title: Electric respirator or chicken rib product?
On February 14, the long out of stock Jingdong self operated platform welcomed the first batch of disposable medical masks that can be ordered and snapped up, with the number of 10000 bags; however, by the time of snapping up, the number of people who have made an appointment has reached 4.23 million, and the probability of winning the lottery is comparable to the national popular civil servant Job test; Jingdong alone, as of the publication date, all online, offline, retail or medical platforms are in short of protective masks. Under the epidemic situation, the world has been without masks for a long time.
Unable to buy masks, the masses had to give full play to the wisdom of the people, self-made 16 layer cotton gauze masks, grapefruit skin masks, and the whole family's bucket masks went to battle. In order to save consumption, it is normal to wear disposable masks repeatedly.
Under the serious shortage of mask resources, the electric mask, which was born in the haze, once again jumped into the public view.
It turns out that you are such an electric mask
After browsing the e-commerce website's electric mask, the reporter's first impression is "a kind of air purifier covering the mouth and nose", I believe most consumers' first impression is the same.
However, Zhang Weichao, director of the new air purification system performance laboratory of the health household appliances testing center of China Household Appliances Research Institute, points out that there are some differences between electric masks and small air purifiers. Electric masks can be divided into two categories: one is positive pressure electric masks; the other is negative pressure electric masks installed on the exhalation valve. On the market, the electric mask with active air supply is more common, which transmits the filtered air to the mouth and nose through the motor. The air purifier is mainly composed of motor, fan, air filter screen and other systems. Its working principle is that the motor and fan in the machine make the indoor air circulate and flow, and the polluted air will be removed or adsorbed after passing through the air filter screen in the machine. In addition, HEPA filter screen, activated carbon, ion or electrostatic adsorption combination are often used in the filter screen of air purifier, which is more complex than the structure of electric mask. The filter material of the electric mask is mainly composed of non-woven fabric, ppcotton and filter layer. Some electric masks will also be added with HEPA filter. However, as most of them are rechargeable products with small motor, resistance, weight and other factors should be fully considered.
At present, compared with N95 respirator, the advantage of electric respirator is to solve the problem of excessive breathing resistance of traditional respirator, especially when some elderly or children wear N95 respirator, it is easy to hold their breath. The electric respirator solves this problem by means of air supply or exhaust.
Novel coronavirus pneumonia is also used to protect against the new crown pneumonia virus. Zhang Weichao believes that products that can prevent particulate matter basically have some protective effects on the virus, but the two can not be directly equated, which involves the particle size of particles.
The novel coronavirus pneumonia is found to be 80-120nm in diameter from the information of various news channels. PM2.5 is a general term for the suspended particles below 2.5 microns in diameter. The diameter of coronavirus is in the nanometer scale, but the droplet carrying the virus may be larger. In addition, the particles are not smaller and easier to penetrate. The most easily penetrated particles are between 100-300 nm. The particles in this range are also used in the national standard test experiment to ensure that all particles can have sufficient filtering effect. At the same time, the virus is mainly spread in the air by attaching to the foam, and the particle size of the foam particles is basically 1-5 μ M. In other words, novel coronavirus pneumonia has a protective effect against the new crown.
According to the data reviewed by CNEEC, N95 masks and disposable medical masks we use are also non-woven materials, i.e. non-woven fabrics, which are made of directional or random fibers. Medical masks are generally made of multi-layer non-woven fabrics, short for SMS structure, i.e. spunbond layer (s) - melt blown layer (m) - spunbond layer (s). The medical mask has at least 3 layers, and the highest number of layers in China is 5 layers, namely smmms. N95 is a mask made of polypropylene nonwoven smmms, which can filter 95% fine particles.
With the scarcity of masks caused by the epidemic, the price of electric masks is also rising. The price range of products ranges from 100 yuan to 500 yuan. In the product introduction, it is often claimed that the purification efficiency is ≥ 95%, ≥ 99%, and even ≥ 99.9%. Some products also have test reports, saying that their electric masks conform to N95 international standards and kn95 domestic standards.
But Zhang Weichao told China home appliances. Com that in their laboratory's previous tests of such products, it was found that their propaganda was often exaggerated.
She said, "there are two main factors that determine the filtering effect of the mask. One is the efficiency of the internal filter element, i.e. whether the filter cotton or the filter material is efficient, which is the most important factor; the other is the fit between the mask and the face during the wearing process, the better the fit, the higher the purification efficiency." In fact, PM2.5 particles blocking efficiency of a large part of electric masks on e-commerce platforms is not as good as N95 masks. But there are also some electric masks that pay attention to brand image, which can achieve 90% - 96% blocking efficiency. Although this is in the laboratory environment, the mask is sealed around by human intervention, but at least the filter material is qualified. In essence, the theoretical protective effect of electric masks should be the same as that of N95 masks.
However, there are also some inferior electric masks with mixed eyes, whose particle barrier efficiency is less than 70%, and even a few products' filtration efficiency is less than 50%; what's more, because of its own design defects, the filtration efficiency is only 23%.
Zhang Weichao also reminded that the filtering effect of electric masks is not positively related to their price, but products with high price may be more comfortable in ergonomic design. She further reminded that "in the process of purchasing electric masks, we should try to choose regular products rather than three no products. Because once the filter element is not qualified, even if its sealing with the face is done well, it will not play a protective role. "
Trendy but not mainstream
At present, the electric mask is still a new product, its industry scale is small, and its brand is in the ranking period. However, the lack of mask resources during the epidemic period provides opportunities for the development of electric masks, and most of the consumers are young.
China home appliance network reviewed the evaluation of several top selling products on Jingdong platform, among which, the better response was that the electric masks solved the urgent need of masks during the epidemic and could not go out; the ventilation feeling was better than N95 and medical masks; under the ventilation condition, water vapor could be discharged and glasses could be prevented from misting; and they could be reused.
The slot points are concentrated in one charge for a short time, which is not suitable for long-time use; the mask is heavy, with strong sense of pressure sharing on the neck, ears, face and bridge of nose for a long time; the air volume is large, when it is outdoors, the air at the mouth and nose is dry and cold; during the use process, the outside dust collection is unable to be disinfected, etc. In addition, it is impossible to judge the protection effect of the product, which is also a big slot for consumers.
According to Zhang Weichao, there is no relevant national standard for the electric respirator industry at present. Combined with this phenomenon, China Household Appliances Research Institute plans to start the formulation of the standard of electric air supply respirator in 2020.
Previously, some consumers reported to China home appliance network that the electric masks sold by some brands on the e-commerce platform were rough in workmanship and dusty in products, suspected to be overstocked in inventory. In addition, whether the filter element has a shelf life, the replacement time of the filter element, and whether the materials such as the ear hook and silica gel in contact with the skin are safe are also within the scope of consumer doubts. With the development of relevant industry standards, we hope that these issues can be followed by rules.
As an innovative product, the emergence of electric masks conforms to the needs of consumers for haze protection and virus protection; however, the lack of reliable basis also creates a big obstacle for everyone's purchase. China home appliance network also expects the product to enter the fast lane of standardized development as soon as possible.