Volume 16, No. 11, November 2016, Pages 2603-2617 PDF(1.15 MB)
Aerosol Chemical Profile of Near-Source Biomass Burning Smoke in Sonla, Vietnam during 7-SEAS Campaigns in 2012 and 2013
Chung-Te Lee1, Shidharth Sankar Ram1, Dac Loc Nguyen1, Charles C.K. Chou2, Shih-Yu Chang3, Neng-Huei Lin4, Shuenn-Chin Chang5,6, Ta-Chih Hsiao1, Guey-Rong Sheu4, Chang-Feng Ou-Yang4, Kai Hsien Chi7, Sheng-Hsiang Wang4, Xue-Chang Wu1
1 Graduate Institute of Environmental Engineering, National Central University, Chung-Li 32001, Taiwan
2 Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
3 Chung Shan Medical University, School of Public Health, Taichung 40201, Taiwan
4 Department of Atmospheric Sciences, National Central University, Chung-Li 32001, Taiwan
5 School of Public Health, National Defense Medical Center, Taipei 11490, Taiwan
6 Environmental Protection Administration, Taipei 10042, Taiwan
7 Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei 11221, Taiwan
- Carbonaceous contents dominate biomass burning PM2.5.
- OC3 and EC1-OP are the most abundant OC and EC fractions, respectively.
- Trajectory paths influence aerosol profile of near-source biomass burning.
- SO42– and NH4+ are enhanced by trajectory paths with anthropogenic origin.
- K+, OC3, EC1-OP, and levoglucosan are tracers of biomass burning.
This study aimed to investigate aerosol chemical characteristics and to obtain the chemical profile of near-source biomass burning (BB) aerosols at a site (675 m a.s.l.) in Sonla, Northern Vietnam. Particulate matter (PM) with an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) was collected over a 24 h sampling period as part of the Seven South East Asian Studies (7-SEAS) campaign. The studies were conducted when BB was highly active — that is, in the spring of 2012 and 2013. The collected particles were analyzed for carbonaceous fractions and water-soluble components, in addition to the mass concentration. Data obtained were further analyzed to determine the stable species profile by classifying the 5-day air-mass backward trajectories. The average PM2.5 mass concentrations were 51 ± 19 µg m–3 and 57 ± 27 µg m–3 in 2012 and 2013, respectively. Carbonaceous contents dominated BB aerosol, with 59% ± 9% and 58% ± 9% in organic carbon (OC) and 9% ± 3% and 10% ± 3% in elemental carbon (EC) of PM2.5 in 2012 and 2013, respectively. Of the 8 carbonaceous fractions analyzed thermo-optically for PM2.5, OC3 (evolution temperature at 280°C–480°C) was most abundant in OC fractions, and EC1-OP (elemental carbon evolved at 580°C minus the pyrolized OC fractions) was predominant in EC fractions in most occasions. Among the measured water-soluble inorganic ions, NH4+ and SO42– widely varied, indicating the influence of different trajectory origins. This finding was confirmed by trajectory classification of aerosol data. The trajectories were also distinguished with respect to char-EC to soot-EC ratio, and water-soluble OC. These characteristics were highest in the trajectory from the BB source area.
Biomass burning; Near-source aerosol chemical profile; Carbonaceous contents; Water-soluble inorganic ions; Water-soluble organic carbon.