Please discuss the causes of smog.

Please discuss the causes of smog. Friends who often pay attention to the weather should know that the smog situation in our country is getting more and more serious. Haze is composed of fog and haze, and there are many reasons for smog. Let's discuss the causes of smog together.

Please discuss the cause of smog: 1 1, the atmospheric aerosol concentration in China is high.

The atmospheric aerosol concentration in China is at a high level in the world, which is conducive to the formation of haze weather. Atmospheric aerosol refers to the general name of solid and liquid particles suspended in the atmosphere, mainly including dust, carbon (organic carbon and black carbon), sulfate, nitrate, ammonium salt and sea salt.

Atmospheric aerosols in different areas of China have different temporal and spatial distribution characteristics. Coal-fired heating in winter in northern China and straw burning in autumn in rural areas will obviously increase the concentration of carbon aerosol; In spring, the western region is affected by dusty weather, mainly dust aerosol. The industry in North China is relatively developed, with more sulfur dioxide emissions. Because high temperature can accelerate the transformation of sulfur dioxide into sulfate, the concentration of sulfate aerosol in North China in summer is higher than that in other seasons and regions.

Aerosol concentration has a great influence on visibility. The high aerosol concentration in China is the main reason for frequent haze weather, and a large amount of black carbon released by heating coal in winter in northern China intensifies the formation of haze.

2. Abnormal atmospheric circulation makes the weather more static.

Static weather refers to the weather in which the near-surface atmosphere lasts for 24 hours or more, the pressure field is relatively uniform, and there is still wind or low wind speed. Turbulence is suppressed under the condition of static weather, especially when the inversion layer appears, the water vapor and particulate matter at low altitude are not easy to spread and it is easy to form haze weather. Quiet weather is more likely to occur in autumn and winter.

3, near-surface atmospheric stability

Pollutants and smog in the atmosphere interact and influence each other, and the main medium is aerosol. The addition of pollutants in smog significantly changes the aerosol concentration, which can promote the condensation of water vapor to form more droplets, and the latent heat released during the condensation of water vapor is beneficial to the rise and expansion of fog area. On the other hand, the increase of cloud droplets and aerosols will reflect and scatter more solar radiation back to the atmosphere, thus reducing the radiation reaching the ground, lowering the ground temperature, increasing the stability of atmospheric stratification, leading to easier normal emission and transformation of aerosol particles in the near-ground atmosphere, and further reducing visibility. It can be seen that the increase of aerosol has a positive feedback effect on the development of smog by affecting the dynamic field and thermal field in the near-surface layer.

4. Due to the secondary reaction of aerosol, the concentration of pollutants increases.

Aerosols can be divided into primary aerosol and secondary organic aerosol according to the formation process. Pollution sources produced by human activities are discharged into the atmosphere, and primary aerosols such as sulfur dioxide, hydrocarbons and nitrogen oxides form new stable particles such as sulfate, nitrate and chloride through chemical reaction and gas particle transformation, that is, secondary organic aerosols. A large number of observation data show that the secondary organic aerosol in the atmosphere contributes a lot to the concentration of PM2.5, and nearly 50% of the particulate matter in air pollutants comes from the secondary reaction. Secondary organic aerosols participate in the formation of more clouds (fog) droplets, which complicates the already serious air pollution and makes the haze weather more serious.

Please discuss the causes of smog. 2. What are the causes of smog?

1, human factors

① Automobile exhaust. Automobile exhaust is the main component of smog particles.

(2) Waste gas generated by burning coal for heating in winter in the north.

(3) Waste gas discharged from industrial production. For example, metallurgy, kilns and boilers, electromechanical manufacturing, automobile repair and paint and building materials production produce a lot of waste gas from kiln combustion.

④ Dust generated by construction sites and road traffic.

⑤ The particle size of growable particles, bacteria and viruses is equivalent to PM 0. 1 ~ PM 2.5. When the humidity and temperature in the air are suitable, microorganisms will attach to the particles, especially the particles of oil fume. After absorbing oil droplets, microorganisms will transform into more microorganisms, which will increase the growth of biotoxic substances in smog.

⑥ Dust "smog" will also be produced in home decoration. Indoor dust is pervasive, which is not only harmful to the health of staff and users, but also increases the cleaning burden. When the dust is serious, it also brings many hidden dangers to the decoration project.

2. Climate factors

① The phenomenon of static wind in the horizontal direction increases. The higher the buildings are built in the city, the obstruction and friction of airflow passing through the urban area will be obviously weakened. The increase of static wind phenomenon is not conducive to the diffusion and dilution of suspended particles in the atmosphere, and it is easy to accumulate around urban areas and suburbs.

② The inversion temperature appears in the vertical direction. The inversion layer is like a pot cover over a city. This inversion phenomenon that the upper air temperature is higher than the lower air temperature limits the vertical movement of the lower air, making it difficult for suspended particles in the air to drift to the upper air and be blocked at the lower air and near the ground.

③ The increase of suspended particles and organic pollutants in the air. With the growth of urban population and industrial development, the number of motor vehicles has surged, resulting in a large increase in pollutant emissions and suspended solids.

How to prevent the harm caused by smog

1, try to reduce going out. In foggy weather, try to reduce going out. If you have to go out, you'd better wear a mask. For people with allergic asthma, wearing a mask is more important. Masks can prevent some allergens such as dust mites from entering the nasal cavity and play a certain protective role.

2. Avoid morning exercises in foggy days. The amount of oxygen needed by the human body increases during morning exercise. With the deepening of breathing, harmful substances in the fog will be inhaled into the respiratory tract, thus endangering health. You can do morning exercises after the sun comes out. You can also switch to indoor sports.

3. Drink more Luohan fruit tea. Arhat fruit tea can prevent and treat throat itching caused by inhaling dirty air in foggy days, and has a good lung moistening effect. Especially in the afternoon, the effect is better. Because the fog is thickest in the morning and almost disappears at noon, people inhale more dust and impurities in the morning, so they can clear their lungs in time when drinking in the afternoon.

4. Wash your hands and face frequently. After going out, you will usually get some smog and dust on your face and hands. Washing your face and hands can achieve nursing effect.