Evaluation of Long-Range Transport and Source Apportionment of Atmospheric PCDD/Fs in Southeast Asia during the Biomass Burning Events.

Autor: Chueh Ting Li, 李珏葶
Rok vydání: 2014
Druh dokumentu: 學位論文 ; thesis
Popis: 102
PCDDs (polychlorinated dibenzo-p-dioxins) and PCDFs (polychlorinated dibenzofurans) which known as dioxin is not only recognized as the lowest LD50 artificial compound in the world, but also one of the persistent organic pollutants (POPs) announced by United Nations Environment (UNEP). The PCDD/Fs emitted into the atmosphere and through dispersive process transported to distant place from the source region, and then deposit to ground surface. Taiwan is located near the mainland China and also the downwind area of East and Southeast Asia, as the result the air quality in Taiwan had great probability influenced by the upwind area which also known as the Long-Range Transport (LRT) event. Therefore, for evaluating the atmosphere PCDD/Fs in Taiwan, to the source apportionment of PCDD/Fs is an important issue. The objective of this study is to find the association of atmospheric PCDD/Fs characteristics between Southeast Asia (Son La and Doi Ang Khang) and downwind area at Mt. Lulin. Furthermore, the PMF (Positive Matrix Factorization, US EPA) and PSCF (Potential Source Contribution Function) will be used in source apportionment of atmospheric PCDD/Fs in this study. Our measurements indicated that the average concentration of atmospheric PCDD/Fs in biomass burning sources region Son La was 19.8±12.1 fg I-TEQ/m3 (n=19) in 2013, and 17.8±12.4 fg I-TEQ/m3 (n=20) measured at Doi Ang Khang,. In the downwind area, Mt. Lulin, the average concentration of PCDD/Fs was obviously lower than the source region, its around 1.89±1.37fg I-TEQ/m3 (n=21) was measured in 2012, and 4.64±3.77 fg I-TEQ/m3 (n=18) was measured in 2013, respectively. The results indicated that PCDD/F concentration in source region were 5 to 20 times higher than the downwind region, especially in the extreme event period. However, the result analyzed by PMF model indicated that the major contribution in Mt. Lulin, was biomass burning (38.7%), open burning (33.4%), and the unknown contributor (19.2%). Moreover, PSCF modeling result shows that there was higher probabilty (above 70%) to measure the extremely high concentrations of PCDD/Fs at Mt. Lulin. The results of PSCF were also displayed, South East Asia and southeast coast of China might be the main contributor in biomass marker such as nss-K+ and NH4+ during the spring period. And the SO42-, mostly produced from anthropogenic activities, had great opportunity contributed from southeast coastal areas China. It can be concluded that atmospheric PCDD/Fs observed in Mt. Lulin was mainly contributed from the air mass thranspot from Southeast Asia which probabaly transported the air pollutant from biomass burning in Southeast Asia or Southeast coast of China on the pathway to the doenwind area.
Databáze: Networked Digital Library of Theses & Dissertations
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