Impacts of ambient air pollution on UNESCO world cultural heritage sites in Eastern Asia: Dose-response calculations for material corrosions

Air pollution adversely affects the built environment. This impact might accelerate the natural deterioration rate of heritage sites and reduce their aesthetic value. This novel study uses multipollutant dose-response functions to investigate the erosion rate of cultural heritage materials in 37 cities in East Asian counties, including China, Japan, and South Korea, between 2015 and 2020. The air quality improved in the studied cities during the study period owing to the efficiency of newly implemented clean air policies. For example, air quality improved regardless of relatively unfavorable meteorological conditions in Japan. Overall, there is a decreasing trend in the surface recession rate of studied heritage materials in China, Japan, and South Korea. However, the results suggest that the cultural heritage resources in Asian cities are still at risk. For example, China experienced the highest estimated degradation rates. Random Forest analysis showed that HNO3, SO2, and PM10 are the primary compounds influencing the corrosion of the built environment materials with a relative importance of 0.42, 0.51, and 0.55, respectively. The results suggest that to preserve sensitive cultural heritage features in the studied cities successfully additional measures are required to reduce atmospheric pollution.