Investigation into the Gaseous SO2 Attack on Sandstone in the Yungang Grottoes

Research reveals that sulfur dioxide (SO2) significantly accelerates the deterioration of sandstone at the Yungang Grottoes, a UNESCO World Heritage Site with over 1500 years of history. The study found that exposure to SO2 under varying humidity and temperature conditions leads to noticeable changes in the stone's luminosity, hue, weight, and chemical composition, including the formation of gypsum. Higher humidity and cyclic temperature fluctuations exacerbate the dissolution of carbonates and hydrolysis of feldspar, increasing ion concentrations like Ca²⁺ and SO₄²⁻ near the surface. These findings highlight the synergistic impact of environmental factors on sandstone decay, offering insights into preservation strategies for such culturally significant sites.

Zhang, Y., Cao, C., Du, H., Huang, J., Guo, X., Luo, Q., & Ren, J. (2023). Investigation into the Gaseous SO2 Attack on Sandstone in the Yungang Grottoes. Minerals, 13(1), 123. https://doi.org/10.3390/min13010123