Professor Shen Yanan from the School of Earth and Space Sciences of the University of Science and Technology of China, together with Dr. Lin Wei from the University of California, San Diego, and Professor of the Master's Chair of the Chinese University of Science and Technology, Professor Mark H. Thiemens of the American Academy of Sciences, etc., are studying the material source and formation of smog in South China. Significant progress has been made in the mechanism. For the first time, the researchers combined the radioactive sulfur isotope (35S) with the stable sulfur isotope (32S/33S/34S/36S), and studied the Wuyishan monitoring station with the background value of the national atmospheric environment as a research point to explore the aerosol in South China. Physical transport pathways and chemical formation mechanisms. The study revealed a very significant 33S and 36S isotope non-mass fractionation signal for the haze sulfate component. The results indicate that the 33S anomaly originates from the photochemistry of the stratosphere (12-50 km above the surface). The reaction, and the anomalous composition of 36S is mainly derived from the combustion process of fossil fuels or biomass. The relevant research results are published online on August 6th in the international authoritative comprehensive academic journal Proceedings of the National Academy of Sciences (PNAS).
In recent years, due to the influence of human, industrial and natural activities, atmospheric pollution and persistent haze weather have seriously affected economic development and human health. Therefore, studying the source and formation mechanism of haze has important theoretical and practical significance. It consists of sulfate, nitrate, organic carbon and black carbon. Therefore, it is highly accurate to determine the stable sulfur isotope of sulfate and explore the cause of its non-mass fractionation signal. It is a guide to the correct understanding of the material source and formation mechanism of haze. Significance. The radioactive sulfur isotope 35S is only produced in the upper atmosphere, with a half-life of 87 days, so it can effectively trace the source and physical transmission route of haze.
By systematically measuring the sulfate in South China aerosol, the sulfur dioxide in the atmosphere, and the stable sulfur isotope of representative coal, the researchers found that the anomalous composition of aerosol sulfates 33S and 36S is different from the isotopic composition of sulfur dioxide and coal in the atmosphere. The results of 35S analysis show that the anomalous composition of 33S is closely related to the change of air mass height, which indicates that the sulfur cycle in the secondary sulfate formation process has undergone photochemical reaction in the stratosphere and then settled to the troposphere and surface. Another important finding of the study is There was no correlation between 36S anomaly and 33S anomaly, but the 36S anomaly showed a very good correlation with the sulfur oxidation rate and the abundance of various biomass burning tracers (levulose, mannan, potassium). The study concluded that the widely observed aerosol sulfate 36S anomalies in East Asia and North America were mainly caused by primary sulfate aerosols generated directly from fossil fuel or biomass combustion. This study demonstrates that sulfur isotopes are tracking different genesis fogs. A powerful means of sulphate source and formation mechanism (pictured):
Schematic diagram of sulfur and sulfur isotope composition of sulphur dioxide and different genesis
Shen Yanan said that the research results provide new research ideas and strong evidence for the material source, transmission pathway and formation mechanism of smog. Different causes of different sulfur isotope anomalies, to explore early life evolution and the early 250,000 years before the Earth The composition of the atmosphere also has important implications. The main objective of the study is to take advantage of our testing techniques and contribute to the development of smog governance policies and the implementation of governance measures by working with domestic and foreign counterparts.
The research work was funded by the Fund's innovative research group, the Guangzhou Elite Project, the Chinese Academy of Sciences' Frontier Science Key Project, and the Higher Education Discipline Innovation Initiative.
