Mapping the evolution of building material stocks in three eastern coastal urban agglomerations of China

The building material stock (MS) plays a vital role in managing and optimizing the urban built environment. This study proposed a novel approach for mapping the evolution of building MS in China's three eastern coastal urban agglomerations (Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD), and Greater Bay Area (GBA)). We divided urban built-up areas into micro-cell units according to the spatial distribution characteristics of nighttime lights (NTL), to estimate the MS, and examine the evolutionary patterns of MS from 2000 to 2020, to reflect the internal urban agglomeration. The results highlighted the total MS in the three urban agglomerations increased from 9.3 billion to 64.4 billion tons, and the YRD had the largest MS scale and the highest growth rate. The spatial-temporal evolution of MS reflected the various development mode of each urban agglomeration. Finally, we provide the prospects in urban renewal and sustainable resource management using our present MS findings.