ICMGP - Conference Presentation

Abstract Information :

This study aims to explore the spatiotemporal variation and long-range transport of atmospheric speciated mercury in the Eastern Waters of Taiwan Island. Three sites located at Green Island, Kenting Cape, and Dongsha Islands were selected for sampling atmospheric speciated mercury. Gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PHg) were simultaneously sampled at the three sites in four seasons to ascertain their spatial distribution, seasonal variation, and long-range transport routes. In terms of atmospheric speciated mercury in the Eastern Waters of Taiwan Island, the highest GEM, GOM, and PHg concentrations were commonly observed at the Green Island, while the lowest ones were found at the Dongsha Islands, respectively. Field measurement results indicated that GEM was the main species in the atmospheric mercury, apportioning as 93.63~96.96% TGM (=GEM+GOM) and 3.04~6.37% PHg. The concentrations of GEM and PHg in cold seasons (spring and winter) were higher than those in cold seasons (summer and fall). However, an opposite seasonal trend was observed for GOM. Backward trajectory simulation and global fire maps both showed that clean air masses were blown mainly from the West Pacific Ocean in warm seasons, resulting in much lower TGM (=GEM+GOM) concentrations than cold seasons when polluted air masses were blown from northeastern Asian countries. Backward trajectory simulation results indicated that the major transport routes of polluted air masses were mainly came from mainland China, Korea Peninsula, and Japan Islands, and commonly passed through the densely populated urban and industrial areas. Overall, Asian continental outflows (ACOs) were transported to the coastal region of North China, then turned clockwise to the Green Island and Kenting Peninsula, and blew atmospheric speciated mercury to the leeward waters due to anticyclone high-pressure system occupied at the Mongolian Plateau.