Volume 16, No. 11, November 2016, Pages 2706-2715 PDF(5.05 MB)
Evaluation of Atmospheric PCDD/Fs at Two High-Altitude Stations in Vietnam and Taiwan during Southeast Asia Biomass Burning
Kai Hsien Chi1, Ngo Tuan Hung1,2, Chuan-Yao Lin3, Sheng-Hsiang Wang4, Chang-Feng Ou Yang4, Chung-Te Lee5, Neng-Huei Lin4
1 Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei 112, Taiwan
2 International Health Program, National Yang Ming University, Taipei 112, Taiwan
3 Research Center for Environmental Changes, Academia Sinica, Taipei 115, Taiwan
4 Department of Atmospheric Sciences, National Central University, Chung-Li 32001, Taiwan
5 Graduate Institute of Environmental Engineering, National Central University, Chung-Li 32001, Taiwan
- Comprehensive dioxin samplings were conducted during 7SEAS/Son La Campaign in 2011.
- On 26 March 2011, the atmospheric dioxins increased to 19.1 fg I-TEQ m–3 at Mt. Lulin.
- Atmospheric dioxins measured at Mt. Lulin and Son La varied followed a similar pattern.
- Significant PCDFs were measured at Mt. Lulin and Son La in biomass burning events.
- The WRF/Chem simulation confirms the source of dioxins attributed to Indochina.
Dioxin and dioxin-like compounds such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are persistent organic pollutants (POPs) generated through human activities. In recent times, extreme weather events such as wild fires have significantly affected the remobilization and successive bioavailability of PCDD/Fs. In Seven South East Asian Studies (7-SEAS), a Southeast Asia biomass burning event that influenced the environmental outcome and transport of PCDD/Fs in Taiwan was investigated on the basis of a climate change situation. During the 7-SEAS campaign on 20–28 March, 2011, significantly high levels of atmospheric PCDD/Fs were observed at Lulin mountain in central Taiwan and in the source region of Northern Vietnam (Son La). Measurements indicated that the patterns of variation of atmospheric PCDD/Fs at both locations were similar, but with a time lag of approximately 2 to 3 days. At Mt. Lulin, there was a significant increase of PCDD/F concentrations from 3.69 to 11.1 fg I-TEQ m–3 and 3.32 to 19.1 fg I-TEQ m–3 to reach their peaks on 23 March and 26 March. In this study, a tracer simulation using the Weather Research and Forecasting model coupled with chemistry was conducted to investigate the effects of the Southeast Asia biomass burning. The combined results of air mass paths simulation and satellite data can be used as evidence supporting the hypothesis that the source of the increasing PCDD/F level is originated from biomass-burning regions in Indochina, particularly Northern Vietnam and Northern Thailand.
Dioxin; Biomass burning; Vietnam; Long-range transport.