Haze, which is a terrible word for people in the north, may not only be in the north, but also in some parts of the south. The harm of haze to human body is self-evident, so how is haze formed? Let's have a look.
Haze affected by meteorological activities
1. The relative humidity of the air near the ground in these areas is relatively high, and the dust on the ground is large. People and vehicles on the ground agitate the dust;
2. There is no obvious cold air activity, the wind force is small, and the atmosphere is relatively stable. Because the air is not flowing, the small particles in the air gather and float in the air;
3. The sky is clear and cloudless, which is conducive to radiation cooling at night, making the air near the ground with high humidity saturated and condensed to form fog.
Haze affected by pollutants
Fog itself is not pollution, but the atmospheric environment that produces fog is in a relatively stable state. The pollutants in the air are not easy to diffuse outward, resulting in agglomeration effect, which will make the pollution more and more serious. In the same way, under the condition of low air pressure and small wind, the combination of urban pollutants and water vapor in the low-level air will also aggravate the degree of haze. Meteorologists say the fog itself is uneven. Therefore, there will be different levels of haze in the same city.
Smog affected by PM2.5
PM2.5 is the 'culprit' in haze weather. There are several main sources. One is automobile exhaust. In recent years, there are more and more cars in the city, and more and more car exhaust emissions, contributing about 60% to PM2.5 in the air of the city. Second, road dust and construction dust. According to the research, road dust is the main source of PM2.5, accounting for about 20% of PM2.5. Third, the secondary pollution produced by the factory. Fourth, the pollutants emitted by burning coal at low altitude when heating in winter. Fifth, the combustion of biomass (straw, firewood) and the smoke and dust generated by waste incineration are also important sources of PM2.5.
There are many other causes of haze around us. There are many sources of particulate matter that are much more influential than cooking, but are often ignored. For example, dust from urban construction sites, burning of agricultural straw, etc. The inputs from urban road excavation, uncovered roads, construction sites, industrial dust and mineral dust outside the city are also important causes of haze. For example, 11% of PM1 in Beijing is composed of element carbon, which mainly comes from urban uncovered roads, construction sites, etc. Haze weather is usually caused by a mixture of various pollution sources. However, in the haze weather of different regions, the effect of different pollution sources is different.
How to prevent haze from affecting health
1. Wear a mask when going out to avoid large particles of dust entering the mouth.
2. Usually drink more water, drink more Chrysanthemum Qi tea and other traditional Chinese tea, prevent diseases, and eat more fruits. It helps to clean the body of bacteria and particle dust.
3. Avoid exercise in foggy days. You can do morning exercises after the sun comes out. It can also be changed to indoor exercise.
4. Don't close the window too tightly. You can choose to open the window for ventilation in a short time when the sun is abundant and the pollutants are less at noon.
5. Try to stay away from the road. During rush hour and night when large cars enter the city, the concentration of pollutants is the highest.