In the fog, it’s better to wear a mask.

As the autumn and winter season arrives, the conditions for pollution spread are gradually deteriorating, and all localities are facing smog. There are a large number of anti-smashing masks in major online stores. Even in the convenience store of 7-11, you can see the protective mask on the counter, which is also attached with "N95, 99% filtering". The label of the eyeball. Apart from the suspicion of commercial hype, is there any evidence that these masks are really effective? Many people may think that wearing a mask may not be as good as eating white fungus Sydney, pig blood, chicken blood, etc. to moisten the lungs and cough and resist smog. However, after research, it is found that the mask can also resist the smog to some extent, therefore, the fog Don't forget to wear a mask when you go out!

It has been medically confirmed that small particles (called PM2.5) of less than 2.5 microns can cause severe inflammatory reactions leading to heart disease, lung disease,
and cancer. However, reducing exposure to polluted air can help improve people's health, reduce the number of emergency visits, and reduce the total number of deaths. Masks can help people reduce exposure to polluted air from the source.

Construction sites around the world are filled with dust, heavy metals and dangerous gases. Tests from independent laboratories have shown that for decades, construction workers have relied on masks made by companies like 3M, which have greatly reduced exposure to polluted air because they have a filtration efficiency of at least 95% for inhaled air. This is the meaning of "95" in the "N95 mask" we often see. (The N95 mask is one of the nine anti-particulate masks certified by the National Institute of Occupational Safety and Health. Under the standard test conditions, the filtration efficiency reaches 95%. N95 is not a specific product name. As long as it meets N95 Standards, and products that pass the review can be called "N95 masks.")

In the test of the N95 type mask, one person wears a mask for about 15 minutes. The person wearing the mask should move in many positions. The mask is attached to a special machine to record the particle concentration inside and outside the mask. If the amount of particles in the air inside the mask exceeds 95%, the mask passes the N95 test. Many masks have received this certificate, and in view of this, it has been determined that these masks can greatly reduce our exposure to the most dangerous PM0.3-PM2.5 particles in air pollution.

By wearing these masks, you can improve your health. This sounds logical, but it is somewhat sloppy. Because so far, no research has been conducted on these mask users for months and years, testing their breathing and determining what improvements have been made. In the absence of sufficient data, the best data we can get from two short-term studies by researchers in Cambridge and Beijing, one of which was published in the Journal of Fibre Toxicology 2009. On the sixth issue of the year. In this study, they studied the passers-by on the streets of Beijing. In August 2008, these researchers recruited 15 young volunteers from Beijing Fuwai Hospital. These volunteers did not smoke, took any medication, and had no previous medical history. The experimental team randomly divided them into two groups and let them walk for 2 hours on the secondary road of the Second Ring Road. As we all know, the Second Ring Road is one of Beijing's many heavily congested roads, filled with various pollutants such as automobile exhaust. When wearing the 3M 8812 mask, their blood pressure was greatly improved. The systolic pressure of the mask group was 7 mm Hg lower than that of the control group, and the systolic blood pressure caused by exercise was significantly increased and the disease was positive. Correlation.

The follow-up study published by the team in 2012 in the Environmental Health Perspectives is more informative. This time they tested people who already had heart disease. The study population consisted of nearly 100 people. They were stable but were taking medication. This time, they used the same 3M mask for more than 24 hours of testing, and no masks for the other 24 hours of testing. When wearing a mask, their heart rate variability, blood pressure, and ischemic stress markers were improved, such as an average reduction in systolic blood pressure of 3 mm Hg when wearing a mask. All of these are considered to be factors in cardiovascular disease such as myocardial infarction and stroke, so any improvement in this objective data will have a large positive impact.

But this study also has some flaws. They admitted that the control group did not wear a mask, and some of the effects may be caused by psychological effects, because the subject may be more relaxed when wearing a mask. But this is already the best study of masks we can find today, which can be used as a reference for the time being.

Why is it so important to study the effect of wearing a mask? Because air pollution does not only cause lung problems, it also causes myocardial infarction, chest pain, and stroke. The study proves that using masks in extreme heat can prevent the onset of myocardial infarction and sometimes save lives.

However, different masks have different anti-mite effects. Ordinary citizens should not blindly wear professional protective masks, because wearing such professional protective masks is subject to training. If you do not understand this knowledge, it is best not to wear them at will. Because these masks are very thick, they can easily cause breathing difficulties after wearing them, and they feel dizzy due to lack of oxygen. Only professionally masked patients need to wear a professional mask. Ordinary citizens who wear masks are better off. The following table shows the test results of the measured values ​​of the sample mask filtration efficiency by the Information Center of Shanghai Quality and Technical Supervision Bureau, which is for your reference only.

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