How to choose which mask can resist haze best
4hw.org: winter is coming, which also means that we will start to fight against haze. The first line of defense in haze days is masks. There are many kinds of masks on the market, with various materials, ranging from several pieces to hundreds. Masks are not the more expensive, the better. Which masks are the best for preventing haze in winter? Let's have a look!
Masks on the market can be divided into cloth masks, N95, surgical masks, activated carbon masks and paper masks, which are suitable for different times of use.
1. Cloth mask or cotton mask: suitable for daily cleaning.
Wang Weisheng, chief physician of the Department of infectious diseases in machai hospital, pointed out that cotton masks have a large gap. Such masks are more suitable for cleaning at home, to block the dust and pollution with larger particles, but the effect is not enough to prevent influenza virus.
Wang Weisheng explained that although most influenza viruses can be spread only when they are attached to the droplets with larger particles, wearing cloth masks can provide a certain degree of barrier, but because the particles of the virus itself are small, in the past, cloth masks only filtered about 37% of the virus particles in the air (referring to particles over 0.3 μ m), and the gap between cloth masks and the face is also large, so if in the hospital Or indoor and other closed space with high virus quantity, the effect of blocking by cloth mask may not be very good.
But if it's just a cold and you're afraid of coughing and sneezing, wearing a cloth mask is still an option.
2. Active carbon mask: it can be used for cycling and cleaning, but its anti air pollution effect is limited.
Masks that emphasize the addition of activated carbon are also not resistant to influenza or severe air pollution Because the function of the active carbon mask is only to absorb volatile organic solvents and impurities in the air. Therefore, it is only suitable for riding a motorcycle, or spraying organic solvents, painting, etc., to prevent odor, oil and other dirt.
Moreover, Wang Weisheng said that activated carbon can no longer play its role after adsorbing a certain amount of volatile organic compounds, so it usually needs to be discarded once in a polluted environment, or the time should not exceed four hours.
3. Mask for medical operation: it can prevent influenza, but it is not enough to prevent air pollution.
Masks commonly used in hospitals and operating rooms can filter more than 90% of the 5-micron particles. When there are respiratory symptoms or influenza prevalence, wearing such masks is enough to block the virus hidden in the nose and mouth droplets. There are usually three layers of nonwovens, usually green, pink or blue.
The functions of the three-layer design are as follows:
Outer layer: PP water splashing material, which can block the droplets or blood adhesion with the source of disease.
Middle layer: special filter screen can block bacteria and dust.
Inner layer: super soft and fine fiber, which can absorb sweat and grease.
However, in order to resist air pollution, the effect of this kind of medical mask is still not enough. Because PM2.5 particles are less than 2.5 microns, medical masks cannot completely filter these fine particles. According to Chen Zhijie, Professor of the Institute of occupational medicine and industrial health of the Public Health College of Taida, most of these masks are plane design, which can't fit the face tightly. The suspended particles can still be absorbed into the body through the gap. In fact, the protection of PM2.5 is only about 30% - 80%.
4. American N95 or European ffp1 mask: it can effectively prevent air pollution.
The main function of such masks is to filter the suspended particles, which can withstand more than 95% of the virus particles of 0.3 μ m or more. The experiment of Taida Public Health Institute found that it can block 80% ~ 99.7% of air pollutants. Moreover, because the three-dimensional shape can be close to the face, the tightness is higher than that of the medical mask with active carbon, and the protective effect is better. Therefore, if the air quality is too poor, it is better to use this kind of mask.
However, if only to avoid influenza, or to visit patients in the hospital, it is still recommended to wear general medical masks. Because N95 mask is difficult to breathe because of its high airflow resistance, people should avoid wearing it for a long time. It is also not suitable for pregnant women with poor lung function, chronic respiratory diseases or asthma. Therefore, Wang Weisheng said that if the air pollution is serious, it is better to simply avoid going out.
5. Paper Mask: it can only be used when other masks cannot be obtained.
Commonly used in hospital vending machines or paper masks with gifts, the effect of filtering particles is the worst, and it is not waterproof. For droplets, saliva, blood and other dirty lack of protection. Therefore, Wang Weisheng suggested that the mask should only be used when other masks cannot be obtained and cannot be used.
Do not wear iron bars on the front and the back, and the waterproof layer shall be outside
It should be noted that the positive and negative effects of masks are much worse, but many people often don't know how to wear a mask. Wang Weisheng reminded that the difference between the front and the back of medical masks is not based on the color, but on the material. The waterproof layer should be on the outside, and the cloth surface layer should be close to the mouth and nose.
If there is a soft metal strip on the mask, it is usually the metal strip facing outwards. Use both hands to press the soft metal strip along the bridge of nose to press the cheek, so that there is no gap between the mask and the face as much as possible.
In addition, the mask is made of special materials. When it is discarded, it can be treated with general garbage, and it does not need to be put into paper for recycling.