Quantifying the relative contributions of key drivers to future changes in PAHs health risks over the Yangtze River Delta: A multi-scenario modeling approach

Polycyclic aromatic hydrocarbons (PAHs), as widespread carcinogenic and mutagenic pollutants, pose significant risks to human health. Their environmental distributions are strongly influenced by climate change, land use changes, and socioeconomic activities. This study employs multi-scenario simulations with an innovative coupling system, the Future Land Use Simulation-Soil and Water Assessment Tool-Multimedia Urban Model (FLUS-SWAT-MUM, FSMM), to quantify the relative contributions of key drivers to PAH concentration dynamics, environmental fluxes, and health risks across six environmental media (impervious surfaces, vegetation, soil, water, sediment, and air) in the Yangtze River Delta under two future climate-socioeconomic scenarios throughout the 21st century. The findings reveal that socioeconomic factors tend to reduce PAH concentrations across all media and primarily govern their distribution in air. PAH concentrations in soil are jointly dominated by socioeconomic and land use changes, whereas those in water show high sensitivity to climate scenarios. Meanwhile, PAH levels in vegetation, sediment, and impervious surface films are predominantly influenced by climate and land use changes. Land use changes significantly influence both PAH degradation and inter-media transfer processes. Among all media, health risks in water exhibit the highest sensitivity to climate scenarios, whereas organic films on impervious surfaces pose the greatest risks, being dually affected by climate and land use changes. This study proposes a novel research framework and provides critical insights for targeted pollution control, highlighting the need to integrate climate adaptation, land use planning, and socioeconomic development to protect environmental and public health.