Professor Shen Yan'an's research group at the University of Science and Technology of China discovered through sulfur isotope analysis that particulate matter generated from coal-fired emissions is one of the main sources of smog in North China. They also provided a new explanation for the formation of black sulfate shells on the surface of European cultural relics, ancient buildings, and statues. Recently, relevant research results were published online in the Proceedings of the National Academy of Sciences in the United States. Haze weather seriously affects economic development and human health, and studying the material sources and formation mechanisms of haze has important theoretical and practical significance. In this work, researchers first systematically collected coal samples from representative coal mines in different geological periods in North China, and then conducted combustion experiments on these coals at 1000 ℃. Subsequently, they collected particulate matter samples with particle sizes less than 2.5 microns, and finally conducted high-precision sulfur isotope testing on the sulfate components in the particulate matter samples. The results show that there is a significant difference in the sulfur isotope composition between coal and its combustion products. Based on theoretical calculations, researchers have found that coal combustion produces non mass sulfur isotope fractionation. Previous studies have shown that non mass sulfur isotope fractionation mainly occurred in rock samples 2.2 billion years ago. Therefore, coal combustion represents a new mechanism for non mass sulfur isotope fractionation, which has important theoretical significance. Further analysis revealed that the isotopic composition of particulate matter produced by coal combustion is very similar to that of sulfates in particulate matter from haze in North China. Previous studies have different understandings of the abnormal sulfur isotope composition of sulfates in the haze of North China, while coal combustion experiments have shown that particulate matter generated from coal combustion emissions is one of the sources of haze in North China. Researchers have also found that anomalous compositions of similar sulfur isotopes appear on black sulfate shells on the surfaces of European artifacts, statues, and ancient buildings. Since the 1960s, European scientists have demonstrated that the formation of black sulfate shells has undergone complex physical and chemical processes, in which atmospheric pollution and volcanic eruptions may have played important roles. Through systematic analysis of sulfur isotopes, researchers have proposed that coal-fired emissions are an important source of sulfate shells on historical sites such as European statues and buildings. This conclusion is highly consistent with the historical high use of coal in the development of industry and agriculture in Europe at that time, which resulted in air pollution. The research results provide new research ideas and evidence for the material sources and formation mechanisms of haze, and provide new scientific basis for the formulation of policies for the prevention and control of atmospheric particulate pollution. It fully reflects the important role of sulfur isotopes in analyzing modern and historical environments. (New Society)