碩士 / 國立中山大學 / 環境工程研究所 / 104 / Taiwan Strait and South China Sea are located at the downwind sites of East Asian Continent where air pollutants can be transported toward the target region. Particularly, South China Sea is the largest marginal sea in the world that influenced the ambient air quality and ecosystem of islands by inland pollution sources. This study investigated the variation of atmospheric mercury with clustered transportation routes in the intersectional region of Taiwan Strait and South China Sea.
This study measured the seasonal variation of the concentrations of speciated atmospheric mercury, and further investigated their spatiotemporal distribution. The concentrations of total gaseous mercury (TGM), gaseous oxidized mercury (GOM), and particulate mercury (PHg) were sampled and analyzed at three sampling sites in the intersectional region of Taiwan Strait and South China Sea. A standard method for sampling and analyzing mercury in air (NIEA Method A304.10C) promulgated by National Institute of Environmental Analysis (NIEA), mostly adopted from USEPA Method IO-5. Moreover, this study applied NOAA-HYSPLIT simulation and Global Fire Map to figure out the transportation routes of polluted air mass by a backward trajectory, a fire spot map, and the correlation analysis of mercury concentration with meteorological parameters and criteria air pollutants. Furthermore, this study also analyzed and compared the concentrations of atmospheric mercury with several islands in East Asian.
Field measurement results showed that the seasonal concentrations of GEM, GOM, and PHg 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. The highest GEM, GOM, and PHg concentrations were commonly observed at Penghu Islands. The results showed that 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. The emission of PHg came mainly from metropolitan areas and very few were emitted from either anthropogenic or mobile sources.
Results obtained from backward trajectories, global fire maps, and meteorological data showed that air masses were mainly came from Pacific Ocean, northern China, and the eastern coast of China during the sampling periods, with the frequencies of 27.50%, 22.50%, and 13.75%, respectively, 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. Air masses were blown mainly from southeastern Asia and the Pacific Ocean during the sampling periods in summer, while the fire maps showed that there were no combustion emissions, thus the concentrations of atmospheric mercury in summer were much lower than those in other seasons. Air masses came mainly from northern China and the eastern coast of China during the sampling periods in fall and winter, from which large amounts of mercury emitted from industrial sources. In spring, air masses were transported to the coastal region of northern China before turning clockwise in the Taiwan Strait due to high pressure system from mainland Asia, which forced the air masses transported directly toward the south, facilitating the transportation of mercury species to the intersectional region of Taiwan Strait and South China Sea.
Comparison of atmospheric mercury with East Asian islands and major cities in the world indicated that the concentrations of Hg 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.
| Identifer | oai:union.ndltd.org:TW/104NSYS5515036 |
| Date | January 2016 |
| Creators | Meng-yen Tsai, 蔡孟延 |
| Contributors | Chung-Shin Yuan, 袁中新 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 132 |
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