Have you bought the right mask in smoggy days? There is a need to open the window for ventilation.

Release time:


Recently, Zhou Qingtao, chief physician of the Department of Respiratory Medicine of Peking University Third Hospital, pointed out in an online popular science consultation at the client of "People's Good Doctor" that everyone knows that masks should be worn to protect themselves in haze days, but what kind of masks to choose, how to wear correctly, and which people are not suitable for wearing masks are all fastidious.

Zhou Qingtao said that the common N95 masks on the market are based on American standards. This standard divides medical protective masks into three categories, one is N category, the other is R category, and the other is P category, which respectively correspond to protective dry particles, oily particles and dry and oily general. Each category is divided into three types, 95, 99 and 100 respectively, representing that the filtering efficiency can reach 95%, 99% and 99.7.

N95 means that 95% of non-oily particles can be filtered out. Our country actually has its own standards for protective masks. Its classification method is similar to the American standard, divided into KN and KP two categories, respectively, corresponding to the protection of dry particles and oily particles. According to the filtration efficiency, it is divided into 90, 95 and 100, and the corresponding filtration effect is 90%, 95% and more than 99%. In China's haze, dry particles are the main ones, so we choose the American standard N95 or our standard KN95 in our daily protection. Its protective effect on PM2.5 is worthy of recognition.

When wearing a mask, you should also pay attention to some precautions, so as to achieve effective protective effect.

First, when wearing a mask, you should make the mask fit with the face. If the mask leaks air everywhere, its protective effect will be greatly reduced. If you can keep the mask closed, so that its protective effect will be greatly improved.

Second, pay attention to the use of time limit. It should be used according to the time limit specified in the instructions of the mask. Once the mask is defaced, it should be replaced in time. Sometimes we say, what if this time limit is not clearly marked? Usually we suggest that protective masks are usually not reusable, the price is not expensive can be replaced every day.

Third, which people need to pay attention to when wearing masks? This is mainly to remind those with chronic diseases, especially patients with chronic respiratory and cardiovascular diseases, because after wearing these masks, their tightness is very good, which will aggravate dyspnea. For this kind of people, they should be cautious in wearing masks, or choose those with slightly lower protective efficacy. For example, I feel difficult to breathe when wearing N95, so I can choose KN90, which may feel more comfortable.

Several masks commonly used in life also have a certain protective effect. For example, medical surgical masks and activated carbon masks, medical surgical masks, which is what we often call disposable masks, are mainly better for the protection and filtration of pathogenic microorganisms. Activated carbon masks for toxic and harmful gas protection will be better. Cotton mask is also what we like to wear, because it is more comfortable to wear, and it is very warm to wear in winter, but it can only filter some coarse particles. For inhalable particles and PM2.5, the filtering effect is relatively poor.

In the indoor should use air purifier, and regular ventilation

Some people think that the haze weather, air pollution is serious, should try to reduce the window ventilation, or even completely cancel the window ventilation. Professor Zhou Qingtao said that this view is wrong! Because the window ventilation can keep the indoor air fresh, oxygen is sufficient, and the window ventilation can destroy the living environment of the pathogenic factor, and the pathogenic factor can be excluded from the outdoor, so as to reduce the invasion of the pathogenic factor to the human body. In addition, opening windows can introduce negative ions in the air that are beneficial to the human body into the room, which will have certain benefits to the human body's immune system, respiratory system, nervous system, and endocrine system. It is beneficial. We should still open windows properly. Ventilation. However, we should also pay attention to the small skills of window ventilation. One is the choice of time period. We can open the window for ventilation around noon when the sun is abundant and the pollutants are relatively light. We can open the window for about half an hour at a time.

After opening the window for ventilation, an air purifier should also be used to filter the furniture air. This air purifier is positive for improving indoor air quality. However, there is a premise that the doors and windows should be closed. If the doors and windows are opened at the same time and the air purifier is used at the same time, the effect is very poor. Also, when choosing an air purifier, its effective purification area should match the indoor area. If it does not match, its purification effect will be greatly reduced.