Volume 16, No. 11, November 2016, Pages 2618-2634 PDF(1.51 MB)
Comprehensive PM2.5 Organic Molecular Composition and Stable Carbon Isotope Ratios at Sonla, Vietnam: Fingerprint of Biomass Burning Components
Dac Loc Nguyen1,2, Kimitaka Kawamura3, Kaori Ono3, Shidharth Sankar Ram1, Guenter Engling4,5, Chung-Te Lee1, Neng-Huei Lin6, Shuenn-Chin Chang7,8, Ming-Tung Chuang9, Ta-Chih Hsiao1, Guey-Rong Sheu6, Chang-Feng Ou-Yang6, Kai Hsien Chi10, Shao-An Sun1
1 Graduate Institute of Environmental Engineering, National Central University, Chung-Li 32001, Taiwan
2 Institute of Geophysics, Vietnam Academy of Science and Technology, Ha Noi, Vietnam
3 Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
4 Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
5 Division of Atmospheric Sciences, Desert Research Institute, Reno, NV 89512, USA
6 Department of Atmospheric Sciences, National Central University, Chung-Li 32001, Taiwan
7 School of Public Health, National Defense Medical Center, Taipei 114, Taiwan
8 Environmental Protection Administration, Taipei 10042, Taiwan
9 Graduate Institute of Energy Engineering, National Central University, Chung-Li 32001, Taiwan
10 Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei 11221, Taiwan
- Organic molecular markers are reported at Sonla, Vietnam.
- Levoglucosan levels confirming the influence of biosmoke on Sonla.
- Burnt materials were non-woody vegetation and more hardwood than softwood.
- Trajectory and organic markers also show anthropogenic or microbial influences.
- Stable carbon isotopic ratios (δ13C) indicate C3 plant and fossil fuel burnings.
This study presents measurements of aerosol chemical properties at Sonla, northern Vietnam (675 m a.s.l.) during spring time, when biomass burning (BB) was very active in the northern Indochina Peninsula, as part of the 7-SEAS (Seven South East Asian Studies) campaign in 2013. The gas chromatography-mass spectrometry (GC-MS) analysis of BB markers in 14 selected samples indicated that mixed softwood, hardwood, grass, and non-woody vegetation were burned. More than 50 organic compounds including levoglucosan, lignin and resin products, sugar and sugar alcohol compounds, fatty acids, phthalate esters, aromatic acids, poly-acids, and biogenic oxidation products (e.g., 2-methyltetrols, alkene triols, 3-hydroxyglutaric acid) were measured in PM2.5. Levoglucosan, a BB tracer, was the predominant species among aerosol sugars, with an average concentration of 1.62 ± 0.89 µg m–3, comprising 2.23 ± 0.5% of PM2.5 mass. For the collection period of the selected samples, backward air mass trajectories were classified into the source regions of Indochina (BBIC), southern China (BBSC), and the South China Sea (BBSS). All resolved molecular compounds show their dominance on the trajectory from BBIC, verifying the BB smoke origin of that region. Trajectory classification provides additional information, such as higher level of diethyl phthalate associated with BBSC trajectory, revealing urban or industrial influence, and more low-molecular-weight than high-molecular-weight fatty acids, indicating distributions with more microbial and lesser plant wax/vegetation burning contributions along the BBSC trajectory. In addition, we report, for the first time, stable carbon isotopic data (δ13C) for PM2.5 aerosols in northern Vietnam, which ranged from –26.6 to –25.4‰ in PM2.5, indicating contributions from burning of C3 plants and fossil fuel combustion.
Indochina; Fine aerosol particles; Biomass burning; Organic molecular markers; δ13C isotope.