Among them, there are six important sources of PM2.5 in Beijing, which are soil dust, coal burning, biomass burning, automobile exhaust and garbage incineration, industrial pollution and secondary inorganic aerosol, and their contributions are 15%, 18%, 12%, 4%, 25% and 26% respectively.
Earlier, it was said that a large number of automobile exhaust emissions in Beijing had a "significant" contribution to smog.
Through the above research, it is not difficult to find that the proportion of automobile exhaust and garbage incineration is 4%, that is to say, the proportion of automobile exhaust alone is less than 4%. Therefore, the statement that the contribution of automobile exhaust is "significant" is contrary to the research results.
What is the chief culprit of smog? There are many reasons for smog, such as volcanic eruption, sandstorm, forest fire, burning straw, burning wasteland, burning coal, dust, industrial emissions and so on.
Stamping a few feet in the ash pile will also cause the PH2.5 value of the area to soar. This kind of thing is not easy to generalize, and there is no culprit. This is just a natural phenomenon, and there is smog when there are no humans on the earth.
The chief culprit of smog has been smog weather since ancient times, and human activities or natural phenomena such as slash-and-burn and volcanic eruption may lead to smog weather. However, after mankind entered the era of fossil fuels, the smog weather really threatened the living environment and health of mankind. Rapid industrialization and urbanization lead to rapid energy consumption, high concentration of population and destruction of ecological environment, which have laid the groundwork for the formation of haze weather. It can be said that industrialization and urbanization are the chief culprits of smog.
Haze, as its name implies, is fog and haze. But there is a big difference between fog and haze. The aerosol system composed of dust, sulfuric acid, nitric acid and other particles in the air causes visual impairment, which is called smog. Haze is haze. Fog is an aerosol system consisting of a large number of tiny water droplets or ice crystals suspended in the air near the ground.
Haze weather is a state of air pollution, and smog is a general term for all kinds of suspended particles in the atmosphere, especially PM2.5 (particles with aerodynamic equivalent diameter less than or equal to 2.5 microns) is considered as the "culprit" causing haze weather. With the deterioration of air quality, cloudy days are increasing and the harm is increasing. In many areas of our country, the smog weather phenomenon is combined with fog as an early warning and forecast of disastrous weather. Collectively referred to as "haze weather".
First, the relative humidity of the air near the ground in these areas is relatively high, and the ground dust is relatively large, which is stirred by people and traffic on the ground;
Second, there is no obvious cold air activity, the wind is small and the atmosphere is relatively stable. Because the air does not flow, the tiny particles in the air gather together and float in the air.
Third, the sky is clear and partly cloudy, which is conducive to radiation cooling at night, so that the air with relatively high humidity near the ground is saturated and condensed to form fog.
Fourth, automobile exhaust is the main pollutant emission. In recent years, there are more and more cars in cities, and automobile exhaust is a factor of smog;
Five, secondary pollution produced by the factory;
Sixth, CO2 and other pollutants emitted by heating in winter. Tian # Cat is imported from America. Pu Weixin tip: Remember to protect yourself when traveling in foggy days.
The sources of PM2.5 are complex, including fine particles directly emitted by coal burning, motor vehicles and dust, and secondary fine particles generated by chemical reactions such as sulfur dioxide, nitrogen oxides and volatile organic compounds in the air. The discharge of pollutants is the chief culprit of haze weather.
Some say it's motor vehicle exhaust, some say it's industrial pollution, building dust, and some say it's street barbecue. Experts can't tell, the culprit is on the run. According to today's news, big cities are still dominated by motor vehicle exhaust emissions.
Where does the smog come from? Who is the chief culprit of smog? First, the relative humidity of the air near the ground in these areas is relatively high, and the ground dust is relatively large, which is stirred by people and traffic on the ground;
Second, there is no obvious cold air activity, the wind is small and the atmosphere is relatively stable. Because the air does not flow, the tiny particles in the air gather together and float in the air.
Third, the sky is clear and partly cloudy, which is conducive to radiation cooling at night, so that the air with relatively high humidity near the ground is saturated and condensed to form fog.
Fourth, automobile exhaust is the main pollutant emission. In recent years, there are more and more cars in cities, and automobile exhaust is a factor of smog;
Five, secondary pollution produced by the factory;
6. CO2 and other pollutants emitted by heating in winter.
Tmall US WeChat reminds: Remember to take good protection when traveling in foggy days.
Reading analysis: The main culprit of PM2.5 smog weather is the complex composition of PM2.5 particles, mainly depending on its source. There are mainly natural sources and man-made sources, but the latter is the most harmful.
Natural sources include: soil dust (containing oxide minerals and other components), sea salt (the second largest source of particulate matter, whose composition is similar to seawater), plant pollen, spores, bacteria and so on. Natural disasters such as volcanic eruptions, forest fires, coal fires and sandstorms that release a large amount of volcanic ash into the atmosphere will transport a large number of fine particles into the atmosphere.
Man-made sources include fixed sources and mobile sources. Stationary sources include various fuel combustion sources, such as power generation, metallurgy, petroleum, chemistry, textile printing and dyeing, heating, cooking, coal and gas or lampblack. The flow source is mainly the tail gas discharged into the atmosphere when various vehicles use fuel in the execution process.
PM2.5 can be converted from oxides of sulfur and nitrogen. These gaseous pollutants are usually caused by human burning fossil fuels (coal, oil, etc.). ) and garbage. In developing countries, burning coal is the main way of household heating and energy supply. Diesel vehicles without advanced exhaust gas treatment devices are also sources of particulate matter. Impurities in diesel truck emissions will lead to more particulate matter.
Indoor, second-hand tobacco is the main source of particulate matter. The source of particulate matter is incomplete combustion, so as long as tobacco products are burned, they will produce serious particulate matter, and using cigarettes with better quality is only self-comfort for smokers (because low odor is more harmful); It is also suitable for gold paper burning, incense burning and mosquito-repellent incense burning.
In addition to natural and man-made sources, gaseous precursor pollutants in the atmosphere will also generate secondary particles through atmospheric chemical reactions, realizing the phase transition from gas to particles. For example:
SO2+H2O→H2SO3
Nitric acid +NH3→NH4NO3
Salt hydrates, such as xCl.yH2O, xNO3.yH2O and xSO4.yH2O, have great influence on PM2.5 with the change of humidity. Water not only forms hydrate with salt compounds, but also forms tiny droplets of salt solution due to the change of humidity.
Pm2.5 is the chief culprit of smog formation, and the burning of plant straw is one of the ways to produce pm2.5, and the word "smog" in this process almost rushed into our sight. 25 provinces were hit by smog, and classes in Nanjing were suspended urgently. More than 0/00 cities in China are seriously polluted by smog, so masks have become a must for going out. You must close the doors and windows when staying indoors. Such serious air pollution suddenly reminds us that smog is not a "patent" for first-tier cities in Beijing and Shanghai. Many people exclaimed, isn't this the fog we saw when we were children? Why is it suddenly toxic? In fact, fog and haze look very similar on the surface, but they are actually different. The difference between fog and haze mainly lies in the size of water content: fog with water content above 90% and haze with water content below 80%. Between 80% and 90%, it is a mixture of fog and haze, but the main component is haze. Puwei core imported from the United States meets the highest standards of medical masks in the United States, and has good filterability, effectively preventing smog inhalation.
Zhao Shanshan, a senior engineer in the Climate Assessment Office of the National Climate Center, said that autumn and winter are the seasons with frequent smog. The analysis of the National Climate Center shows that specific meteorological conditions are an important reason for the frequent occurrence of haze weather in recent days. Since September 20 13, the cold air affecting the central and eastern regions of China has little activity, weak intensity and low surface wind speed, which is conducive to the accumulation of water vapor and the formation of smog in the lower atmosphere. In addition, the warm and humid air flow on the south side of the Qinghai-Tibet Plateau is very active, which makes the southwest warm and humid air flow from the Indian Ocean extremely active. This warm and humid air flow transported rich water vapor to the central and eastern regions of China along the southwest route, and reached the vicinity of Beijing, which significantly increased the humidity in these areas, and was also conducive to the formation of low-level inversion, which was very conducive to the formation of haze weather. However, it should be noted that although meteorological conditions play an important role in the formation of haze weather, tracing back to the source, exceeding the standard of atmospheric particles is the root cause of haze, that is, in addition to meteorological conditions, there are industrial production, vehicle exhaust emissions, heating in winter and coal burning. The increase of atmospheric particulate matter (including coarse particulate matter PM 10 and fine particulate matter PM2.5) is an important factor for smog. The atmospheric particulate matter that plays a major role in the formation of smog is PM2.5. It can be said that PM2.5 is the chief culprit in the formation of smog.
PM2.5 refers to particles with a diameter less than or equal to 2.5 microns in the atmosphere, also known as particles that can enter the lungs. Its English name is Particulate Matter2.5, or PM2.5 for short. Its diameter is less than 1/20 of the thickness of human hair.
The source of P M 2. 5 is very complex, mainly divided into primary particles and secondary particles. Primary particles are classified as natural particles.
There are two kinds: source and artificial source. Natural sources mainly come from soil dust particles, aeolian dust, sea salt particles, plant pollen and so on. Artificial source owner
Fly ash produced by fossil fuels (coal, oil, natural gas, etc.). ), motor vehicle exhaust dust, industrial dust and biomass burning fly ash, roads.
Dust and so on. Gaseous substances in secondary particles include SO2, nitrogen oxides, VOC, etc. And their sources are extremely complicated. It is generally believed that they come from fuel combustion, automobile exhaust, industrial production, catering in commercial and residential areas, etc. The components of PM2.5 generally include inorganic components, organic components, elemental carbon and heavy metal elements. Its composition and quantity are related to the economic development level, energy structure, production and management methods of various countries and regions.
Straw combustion directly emits primary particulate matter, and the flue gas (emitted by straw combustion) contains' organic aerosol', which can form PM2.5 "
(1) Open the window less in foggy days. It is best not to go out and do morning exercises. It is not recommended to open the window for ventilation in the morning and evening in foggy days. Better wait until the moon comes out. Smog weather is a "dangerous day" for patients with cardiovascular diseases, especially for the elderly with respiratory diseases and cardiovascular diseases. It is best not to go out in foggy days, and it is not suitable for morning exercise, otherwise it will induce diseases and even heart attacks, which will be life-threatening.
(2) Drink more "lung-clearing and dust-removing" teas, such as Tongplatycodon grandiflorum tea, Tongshen tea, Tongplatycodon grandiflorum granules, orange stem soup, etc. Tongplatycodon grandiflorum tea has the functions of clearing fire and filtering lung dust, which can enhance the ability of alveolar cells to expel toxic fine particles and help the human body to expel harmful substances such as PM2.5 particles accumulated in the body.
(3) Try to reduce smoking or even not smoking. There is a large amount of PM2.5 in smoke, which will cause direct and indirect harm to human body. If you can't stop people around you from smoking, you should try to stay away from the smoke.
Protecting the environment is everyone's responsibility.
Is petroleum coke the chief culprit of smog? Petroleum coke contains a lot of haze-causing substances, which is the main cause of haze according to the current scientific data.