Calculation of carbon emissions and analysis of carbon emission reduction potential during the construction stage of metro stations

Metro is a key component of the urban rail transportation network, showcasing significant advantages and potential in promoting green and low-carbon travel modes. A typical metro station construction project in Qingdao was taken as an example, and the emission factor method and scenario analysis method were selected to systematically assess the carbon emission of this metro station construction and examine its potential for carbon emission reduction. The results show that by 2022, the construction of Qingdao metro stations generated approximately 16.32 MtCO2e in cumulative carbon emissions, with building material production contributing the highest share at 93.19%. Additionally, by promoting the use of renewable building materials, it is expected that the carbon emission intensity of metro construction in Qingdao will be reduced by a maximum of 8.85% from 2022 to 2035, which is important for promoting the transition of metro construction to decarbonization.