The color influence of dust in air pollutants on architectural painting: a case of archery tower at the West Gate in Shaanxi, China

At present, under the influence of environmental pollution, the color of architectural painting gradually darkens, loses luster, and even cracks when the pigment falls off, which seriously affects the long-term preservation of architectural painting. In order to study the damage mechanism of dust particles to the color of the architectural painting, this study took the archery tower at the West Gate as the research object, monitored the temperature and humidity of the indoor environment, and analyzed the composition of the dust by ICP-MS, IC, and XRD. The experimental results showed notable fluctuations in the indoor humidity in inner the archery tower at the West Gate during the monitoring period from January to March, which were not conducive to the preservation of wood-colored paintings. The 24-h average PM_2.5 and PM₁₀ concentrations, measured over 2 days in January, were beyond the National Ambient Air Quality Standard norms, and PM contains a large amount of soluble salts such as sulfate and nitrate, causing serious salt erosion and damage to the color painting layer. Through the simulation experiment of the color painting layer, it was revealed that the dust particles deposited on the surface of the color painting layer change the spectral characteristics of the color painting layer, and then cause the color layer to lose its original hue, fade become blurred, or darken. It was anticipated that this research would serve as a valuable reference for the preventive protection of the color painting layer of the archery tower at West Gate.