"The latest research on the smog caused by motor vehicle emissions accounted for only 4% of the research results on the Internet. I think that it does not meet the objective facts at all. As far as the original text is concerned, there are major flaws in research methods and ideas; as far as the data in the paper is concerned This so-called conclusion is not completely established. We must not let such erroneous scientific research results mislead the governance of China's smog." One year ago, Professor Zhuang Guoshun, an atmospheric scientist at Fudan University, specially called the newspaper for an emergency call. Through the media "to see and hear". This statement originated from the end of 2013, a team of researchers from the Institute of Atmospheric Physics of the Chinese Academy of Sciences, Zhang Renjian, published a paper in the English magazine "Atmospheric Physics and Chemistry", introducing them to Beijing PM2.5 using the positive matrix factor method. The most important sources are soil dust, coal combustion, biomass burning, automobile exhaust and waste incineration, industrial pollution, and secondary inorganic aerosols; the average contribution of these six is ​​15%, 18%, 12%, 4%, respectively. 25% and 26%, if coal, industrial pollution and secondary inorganic aerosols are combined, fossil fuel combustion emissions become the main source of PM2.5 pollution in Beijing. Secondary inorganic aerosol components contain motor vehicle emissions “The secondary inorganic aerosol is regarded as one of the six important sources, and it is considered that automobile exhaust and waste incineration account for only 4% (only 3% in the original English text). The problem is that the secondary inorganic aerosol is How can the formation process and mechanism of particulate matter be used as a source? From this point, it can be seen that the author lacks the basic common sense of source analysis. Such articles and their reports in the media will prevent air pollution in China. It brings great misleading and serious consequences. If the amount of secondary inorganic aerosols from motor vehicle emissions is taken into account, it has already reached about 20%. How can it be said that motor vehicle emissions only account for 3% of the causes of smog? "Zhuang Guoshun said. Professor Zhuang said that the secondary inorganic aerosol is a secondary pollutant that undergoes chemical changes in the atmosphere to form secondary contaminated inorganic particles. Secondary inorganic aerosols mainly include sulfates, nitrates, ammonium salts, etc. For example, sulfur dioxide forms sulfates in the atmosphere, and nitrogen oxides form nitrates in the atmosphere. Now science has concluded that motor vehicle emissions in secondary inorganic aerosols also account for a considerable portion. "In addition to the nitrogen oxides emitted by motor vehicles, organic aerosols formed by organic hydrocarbons emitted by motor vehicle exhausts, black carbon emitted by motor vehicles, and dust from motor vehicles are important sources and components of haze formation. Part. With these parts, the contribution of motor vehicles far exceeds the so-called 3% in the article." Professor Zhuang emphasized the "serious mistakes" of the article. On the eve of New Year's Eve, Pan Tao, dean of the Beijing Municipal Environmental Protection Research Institute and director of the National Urban Environmental Pollution Control Engineering Technology Research Center, also said that the contribution of motor vehicle emissions to PM2.5 concentration is mainly two aspects. Sol particles, that is, PM2.5 directly discharged, and secondary inorganic aerosol particles, that is, PM2.5 generated by chemical reaction of gaseous pollutants such as nitrogen oxides and volatile organic compounds emitted by automobiles in the atmosphere. “If you carefully analyze the conclusions of Researcher Zhang Renjian, the six sources of PM2.5 in Beijing include secondary inorganic aerosols, with a contribution ratio of 26%. There is a considerable part of the nitrogen oxides emitted from motor vehicles. So even if it is cited He concluded that the impact of motor vehicles is not limited to 4%." Reducing motor vehicle emissions is an important part of managing smog "To reduce smog now, it is mainly to reduce the burning of fossil fuels such as coal and reduce the emissions of motor vehicles." Zhuang Guoshun said. He believes that China's energy structure cannot be changed in the short term, coal is still the most important fuel, and research statistics show that the main emission pollution of coal is sulfur dioxide. During the 12th Five-Year Plan period, China has made great achievements in coal desulfurization. work. According to statistics, in 2000, the emission of sulfur dioxide in China's atmosphere was 35 million tons. By 2013, the emission of sulfur dioxide was still 35 million tons. Due to the promotion of coal desulfurization technology, it means that it has been in the past ten years. Although the industry has grown tremendously, the total amount of sulfur dioxide emitted by coal has not increased. However, in the past ten years, China's air pollution has become more and more serious, especially the visible haze has been very serious. What is the most direct cause of severe haze? From the above analysis, and taking into account the sharp increase in the number of motor vehicles in the past few years, it is clear that motor vehicle emissions are the most important cause of smog. “And we have analyzed the composition of PM2.5 in atmospheric haze many times and verified our conclusions.†Zhuang Guoshun said. Zhuang Guoshun's research team began monitoring the content of atmospheric particulate matter in China from 2000. It was found that PM2.5 in Beijing and Shanghai mainly comes from human activities, especially industrial emissions and motor vehicle emissions. In Shanghai airborne particles, the main form of soluble ions in the particles is highly water-absorptive such as sulfates, nitrates, ammonium salts and organic acid salts. In addition to the fact that the sulfates are mainly derived from coal combustion, the main source of other components is the emissions of motor vehicles. "When I came back from the United States more than a decade ago to work in Beijing, I was reminded to pay attention to motor vehicle emissions. Until now, the smog is so serious that China's smog management can no longer detour." Pan Tao also said that the results of the analysis of the source of PM2.5 in Beijing, the domestic China Academy of Environmental Sciences, Peking University, Tsinghua, Beijing Environmental Monitoring Center, including other research groups of the Institute of Atmospheric Physics of the Chinese Academy of Sciences, have also published their respective The study concluded that the contribution of motor vehicles is generally considered to be between 10% and 50%, and most of them are considered to be between 20% and 30%. The difference is large, mainly due to the variability of PM2.5 components, the methods used, and the researchers' Subjective factors and other reasons. But these studies all point to the same conclusion - motor vehicle emissions are one of the main sources of air pollution in Beijing, and this is beyond doubt. And Pan Tao said: "From the scientific method, the source analysis of PM2.5 is to analyze the chemical composition of the PM2.5 sample taken, and to estimate the where the pollutants come from through a certain model calculation, it is an indirect The method that directly reflects the contribution of motor vehicle emissions is the list of pollution sources. Since the survey of pollution sources in 2007, the Beijing Academy of Environmental Sciences has been committed to the preparation and updating of the Beijing air pollution source inventory list. According to our list, Beijing The city produces two of the most important precursors of PM2.5 (the gaseous substances that can generate PM2.5 through the reaction), nitrogen oxides and volatile organic compounds, and the proportion of motor vehicle emissions is as high as 42% and 32%, respectively. It is more directly confirmed that motor vehicle exhaust is the main culprit of air pollution in Beijing." Hollow Plate Welding Head,Medical Device Straight Circular Ultrasonic Fixture,Automotive Ultrasonic Straight Cylinder Mold,Ultrasonic Straight Cylinder Forming Die Changzhou Piling Automation Technology Co., Ltd. , https://www.plultrasonicmould.com
August 11, 2024