Century-long socioeconomic-air pollution transitions revealed by lake sediments in Northeast China

Understanding the long-term interplay between air pollution and socioeconomic development is essential for evaluating sustainability transitions, yet its long-term dynamics remain poorly understood. Most existing studies rely on static indicators and lack continuous environmental records, limiting the detection of nonlinear transitions and threshold effects. By integrating records of combustion-derived pollutants (polycyclic aromatic hydrocarbons, spheroidal carbonaceous particles, and soot with its fossil fraction) collected from a 121-year sediment core in Sihailongwan Maar Lake with historical socioeconomic datasets, this study constructs the coupling index based on the rate of change to characterize the temporal evolution of atmospheric–socioeconomic linkages, and quantifies the relative contributions of key driving factors to historical pollution trends using Logarithmic Mean Divisia Index decomposition. Our results reveal a transition towards weak decoupling in the early 21st century, with an Environmental Kuznets Curve turning point for combustion-derived pollution emerging at a per capita GDP of approximately 11,500–13,320 Yuan (in constant 2015 prices). Decomposition analysis shows that from 1900 to 2021, economic out increased air pollution levels by a factor of 245 and population growth by a factor of 30, whereas controls in energy intensity and emission intensity reduced them by factors of 131 and 117, respectively. This work underscores the potential of geological archives to trace human–environment coevolution, offering insights for addressing sustainability dilemmas in industrial regions.