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General Session 4: Marine environment, ecosystem & sustainability |
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Field measurement of atmospheric speciated mercury at two subtropical islands in the Taiwan Strait and South China Sea
Monday 9th @ 1035-1055
Room 1
Meng-Yen Tsai, Institute of Environmental Engineering, National Sun Yet-sen University
Ting-Shuo Chen, Institute of Environmental Engineering, National Sun Yet-sen University
Chung-shin Yuan* , Institute of Environmental Engineering, National Sun Yet-sen University
Presenter Email: ycsngi@mail.nsysu.edu.tw
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| This study aims to measure the concentrations of atmospheric speciated mercury with clustered transportation routes in the intersectional region of Taiwan Strait and South China Sea. Two islands, the Penghu Islands and the Dongsha Islands, were selected to investigate the seasonal variation of the concentrations of speciated atmospheric mercury. The concentrations of total gaseous mercury (TGM), gaseous oxidized mercury (GOM), and particulate mercury (PHg) were sampled and analyzed. A standard method (NIEA Method A304.10C) adopted mostly from USEPA Method IO-5 used dual gold amalgam to collect total gaseous mercury (TGM), while particulate mercury (PHg) was collected by a quartz fiber filter. Moreover, a manual denuder coated with 2.4 M aqueous KCl solution was used to collect gaseous oxidized mercury (GOM). This study further applied NOAA-HYSPLIT simulation and Global Fire Map to figure out the transportation routes of polluted air masses by a backward trajectory, a fire spot map, and the correlation analysis of mercury concentration with meteorological parameters and criteria air pollutants. Field measurement results showed that the concentrations of GEM, GOM, and PHg at the Penghu Islands were generally higher than those at the Dongsha Islands. The seasonal variation of GEM, GOM, and PHg concentrations were ordered as spring> fall> winter> summer, spring> summer> fall> winter, and spring> winter> fall> summer, respectively. The average concentration of GEM, GOM, and PHg were 2.57±0.67 ng m-3, 19.60±7.87 pg m-3, and 0.16±0.04 ng m-3, respectively. TGM was the main mercury species in the gas-particulate partition, and atmospheric mercury apportioned as 92.54~96.17% TGM and 3.83~7.45% PHg. Backward trajectories showed that air masses were mainly came from Pacific Ocean, northern China, and eastern coast of China with the frequencies of 27.50%, 22.50%, and 13.75%, respectively, during the sampling periods, while the concentrations of GEM were 2.55±1.07 ng m-3, 2.79±0.75 ng m-3, and 3.16±0.79 ng m-3, respectively. Overall speaking, the concentrations of atmospheric mercury in the intersectional region of Taiwan Strait and South China Sea were generally lower than the islands in East Asia and mainland China, but higher than Japan, EU, and USA. Keywords: Atmospheric speciated mercury, spatiotemporal distribution, clustered transportation routes, gas-particulate partition |
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