Mapping material stocks in buildings and infrastructures across the Beijing-Tianjin-Hebei urban agglomeration at high-resolution using multi-source geographical data

Spatial patterns of material stocks in buildings and infrastructures are crucial for understanding resource use, spatial planning and environmental management. So far, spatially explicit stock-driven approaches face substantial data limitations, requiring costly and time-intensive efforts to map stocks at urban micro-scales. Herein, we developed a volume-based framework for material stocks mapping in buildings and infrastructures at a 10 m resolution, applied across the entire Beijing-Tianjin-Hebei urban agglomeration (BTH-UA) in China, a key growth pole for regional economic development. We integrated multi-source remote sensing data, GIS products, crowdsourced data, and material intensity databases, covering ten bulk materials. The findings reveal that the total mass of buildings and infrastructures in BTH-UA amounts to 195,000 Mt, equivalent to 182 t/cap, 2.43 Mt/ km2. Material stocks are spatially clustered and correlate with the population size and economic activity of the secondary industry. This research contributes to the quantitative description and detailed mapping of material stocks in built environment.