Scientists are working hard for this. The “Pioneering and Control of Atmospheric Hazeâ€, a strategic leading science and technology project launched by the Chinese Academy of Sciences in September 2012, has carried out 5 projects and 25 topics in terms of traceability of haze, numerical simulation, monitoring technology, and control technology. Research. The special team is composed of more than 300 scientists and technicians from 14 research institutes of the Chinese Academy of Sciences and 8 out-of-hospital units including Tsinghua University, Peking University, and China Academy of Environmental Sciences. The first phase of the study will last 5 years.
The latest research results of the "Atmospheric Haze Tracking and Control" task force believe that the recent strong haze event in North China is the result of the combined effects of atmospheric stability, anthropogenic pollution emissions, floating dust and abundant water vapor in the central and eastern regions under abnormal weather conditions. An event in which natural factors and human factors work together.
However, external factors such as weather are hard to reach by manpower, and the control of smog can only be started by controlling the discharge of pollutants. Which pollutants have the greatest impact on causing severe haze?
"The composition of the haze is quite complex. From elemental analysis, it can almost fill the periodic table, and there are more than 30,000 organic molecules." Wang Yuesi, a researcher at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, said that motor vehicle emissions in Beijing are the largest source of urban PM2.5 For the quarter, coal-fired and foreign transportation account for one-fifth. "Pollution emissions from vehicles at low speeds are 5-10 times higher than normal driving, so to prevent the occurrence of heavy haze pollution in Beijing and Beijing-Tianjin-Hebei, Beijing should focus on solving motor vehicle road congestion; surrounding areas should focus on Solve the control of the desulfurization, denitrification and dust removal of coal-burning and its volatile organic emissions. "
Controlling the discharge of pollutants is a permanent solution, but it is not an overnight success. If severe haze weather can be forecasted in advance, can temporary emergency measures be taken to curb the occurrence of strong haze?
"If a national scale atmospheric PM2.5 numerical forecast business model is established, it is expected to forecast the time, scope and intensity of high-concentration smog events 3 to 4 days in advance, and implement precise strikes to effectively curb the occurrence of heavy smog events. Wang Zifa, a researcher at the Institute of Atmospheric Physics of the Chinese Academy of Sciences and director of the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, said that the Institute of Atmospheric Sciences of the Chinese Academy of Sciences used the self-developed numerical model of air quality NAQPMS to simulate the haze event The regional atmospheric haze formation trend and coverage, but the simulation results for the extremely high PM2.5 concentration values ​​are obviously low.
"The London smog incident in the 1950s was mainly due to soot pollution caused by coal combustion; the contemporary Los Angeles photochemical smog incident was mainly due to composite air pollution caused by vehicle exhaust, and its phases are relatively clear," atmospheric ash He Hong, chief scientist of the Haze Tracking and Control Task Force and a researcher at the Eco-Environmental Research Center of the Chinese Academy of Sciences, said, "With the rapid leap-forward development of our country, the process of atmospheric pollution in different stages experienced by developed countries has been compressed to this special stage. The type of air pollution has been transformed into a current type of severe compound air pollution with multiple types of coal-motor vehicle-industrial pollution and high load coexistence. This is a new situation that developed countries have not experienced. "
He Hong believes that there are currently two major difficulties in the study of smog: First, the source of PM2.5 in China is unclear and the source weight is unclear. The reason is mainly due to the key precursor pollutants and key chemistry generated by the second generation of PM2.5 The mechanism is unclear. The second is that the control plans for different regions in China are not clear. The contribution of precursor pollutant transboundary transport to the formation of PM2.5 is lack of systematic research, which makes it impossible to determine the control scheme of pollutants in different regions. "Simple control of single pollutants has no significant effect on the control of PM2.5. To truly control PM2.5, regional joint prevention and joint control is required."
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