Greenhouse gas emissions from construction machinery in China: Historical trends and prospective reduction pathways.

China's rapid urbanization has driven extensive construction activities, leading to the widespread deployment of fuel-powered construction machinery and substantial greenhouse gas (GHG) emissions. We combined surveys on machinery units, operational hours, and load factors to quantify GHG emissions (CO2, CH4, and N2O) from construction machinery in China from 2013 to 2022. Emissions projections were modeled using the low emissions analysis platform (LEAP) under baseline, market-driven, policy-guided, and regulatory-driven scenarios, with parameters including machinery stock, electrification rate, and fuel consumption per hour. The results indicate that from 2013 to 2022, the number of machinery units increased significantly, driving parallel growth in CO2 and N2O emissions, whereas CH4 emissions demonstrated consistent annual decreases because of emission intensity. CO2 equivalent (CO2 eq) emissions increased by 17 % from 2013 to 2021 and then decreased by 2.6 % to 7.3 × 107 t CO2 eq in 2022, with CO2 accounting for 98 %-99 % of total GHG emissions and N2O and CH4 accounting for 1.2 % and 0.1 %, respectively. The primary emission sources were China Stage Ⅲ machinery (69 %), excavators (64 %), and high-power equipment (> 130 kW, contributing 30 %-90 %). Spatially, East China accounted for 47 % of national emissions in 2022, followed by Central China (18 %), which is related mainly to the advanced economic development and infrastructure construction demands. The scenario analysis showed that reducing machinery numbers, enhancing electrification, and improving fuel efficiency could yield substantial mitigation benefits, with the regulatory-driven scenario achieving up to 97 % GHG reduction potential.