Work

Atmospheric Mercury Variability at a High-Altitude Site in East China: The Significant Role of Temperature-Driven Natural Source Contributions

Year: 2025

Type: article

Abstract: Both anthropogenic and natural sources regulate the temporal variability of atmospheric mercury. While most studies focus on ground-level observations, our understanding of atmospheric mercury characteristics and influencing factors in the upper air remains limited. Here we present online measurements of total gaseous mercury (TGM) at a high-altitude mountaintop (1545 m asl) in developed East China. Significant differences in TGM concentrations were observed during the cold season (2.35±0.65 ng m-3) and warm season (3.61±1.78 ng m-3). Unlike the decreasing trend of air pollutants from cold to warm seasons, TGM concentrations increased clearly with rising temperatures. A trained Generalized Additive Model (GAM) revealed that anthropogenic emissions dominated TGM variability in the cold season, while wind direction and temperature-driven natural sources played the leading role in the warm season. Scenario analyses replacing individual variables in the warm season indicated that contributions from anthropogenic emissions slightly decreased, while natural emissions associated with elevated temperature increased TGM by 1.79 ng m-3 on average. Our findings highlight the significant role of natural source emissions that are nonlinearly driven by temperature in the variability of atmospheric mercury in the upper air of developed regions in the context of anthropogenic emissions declining and global warming.

Source: ACS ES&T Air

DOI: 10.1021/acsestair.5c00184