A practical simulation of carbon sink calculation for urban buildings: A case study of Zhengzhou in China

Cement and other cementitious materials in buildings can react with CO2 in atmosphere, leading to the carbonization. Predicting the precise uptake of CO2 of urban buildings is crucial to addressing the loss of carbon sinks. Here, we systematically studied the carbon sinks of urban buildings in the third ring road area of Zhengzhou city. First, we developed an effective model described by the exposed area and completion time of buildings based on Fick's second law. Using this model, we studied the carbon sinks of urban buildings in the past 50 years and predicted the carbon sinks in the next 10 years. The total carbon sink is 1.648 million tons in the last 50 years. The carbon sink density across the study area shows a heterogeneous distribution, with high density concentrated in the central and left half. In addition, carbon sinks exhibit time-dependent characteristics, with the period 2002-2022 accounting for 77.7% of the total for the entire 60-year period. The carbon sinks and spatial distribution of carbon sink density are not only critical to address lost carbon sinks, but also provides important information for future urban planning and should therefore be of wide interest to environmental scientists, architects and government staff.