Why is it said that staying indoors in foggy days will reduce the harm? Isn't the indoor and outdoor air the same?

The smog is serious, how to purify the indoor air?

Smog days repeatedly "hit", indoor air suffered, and the market for air purification products also caught fire. At present, there are many kinds of air purification products on the market, and the quality is uneven. Many consumers buy them blindly and cannot play the expected protective role. In fact, there are many practical ways to purify indoor air.

Air pollutants generally include polluted gases and suspended solids, such as bacteria, viruses, dust, pollen, mold spores, as well as odors, toxic chemicals and toxic gases. In addition to outdoor sources, indoor smoking, harmful gases released by home improvement furniture, kitchen fumes and human activities are all important sources of indoor air pollution. In western countries, hospitals or families buy air purification devices to protect allergic patients. In contrast, China's environmental and indoor air pollution control has just started. Most consumers buy air purification devices to remove PM2.5 and decoration pollution. Therefore, when buying products, we must first make clear our own needs.

At present, there are two most mature air purification technologies: one is the physical technology using HEPA filter (high efficiency particulate air filter), which is also the mainstream technology in the world at present. The air purifier with ordinary filter screen can filter suspended particles above 0.3 micron, with an efficiency of 99.97%. It has a good filtering effect on chemical smoke, bacteria, dust particles and pollen, but it cannot filter out harmful gases. Although the filter screen with large aperture can not filter out fine particles, it can well remove larger particles such as plant fibers, seeds, dust, mold and animal hair. The disadvantage of filter screen purifier is that the filter screen needs to be replaced and the price is high. The other is electrostatic dust removal technology. The purifier of this technology does not need to replace the filter screen, but it is easy to produce secondary pollution by-products such as dust and ozone.

The New York Times pointed out that three aspects should be made clear when purchasing air purification devices. Waberg Lee, the website director of "American Air Purifier", pointed out in an interview that the first is filtration performance, and products using HEPA filtration technology should be selected to filter out fine particles; Second, we should consider the area of the house. The applicable area of the purification device should be compared in detail according to the actual situation and the instructions. The air purifier should be placed in the place where we often stay every day, such as the office or bedroom. Third, the higher the gear, the louder the fan noise. If the purifier has many gears, you should choose the appropriate gear according to your own needs when purchasing.

According to the article published on the website of American doctor of network medicine, there are many ways to purify indoor air. Neil Scott, a respiratory care expert in new york, said: You often open the window after covering the filter. Closing doors and windows often in winter is not conducive to purifying indoor air. The best way is to cover the window with a special filter to block most outdoor pollutants. The pore size of the filter screen can be determined according to the outdoor environment. If the air conditioner and humidifier are used together, the indoor dryness will aggravate the dust accumulation phenomenon. At this time, it can be adjusted with a humidifier. When the humidity is too high, the air is easy to attach germs, PM2.5 and so on. Into the human respiratory tract. At this time, the air conditioner can play a drying role and suck away PM2.5 and pollen. Ask technicians to check the tightness of gas valves regularly every year to avoid gas leakage. Keep the kitchen well ventilated and turn on the range hood for a while after cooking to avoid the accumulation of polluted gas. In addition, use air fresheners or cleaning products as little as possible, which contain many pollutants such as aldehydes and benzene.