Articles | Volume 17, issue 11
Research article
12 Jun 2017
Research article |  | 12 Jun 2017

Influence of biomass burning from South Asia at a high-altitude mountain receptor site in China

Jing Zheng, Min Hu, Zhuofei Du, Dongjie Shang, Zhaoheng Gong, Yanhong Qin, Jingyao Fang, Fangting Gu, Mengren Li, Jianfei Peng, Jie Li, Yuqia Zhang, Xiaofeng Huang, Lingyan He, Yusheng Wu, and Song Guo

Abstract. Highly time-resolved in situ measurements of airborne particles were conducted at Mt. Yulong (3410 m above sea level) on the southeastern edge of the Tibetan Plateau in China from 22 March to 14 April 2015. The detailed chemical composition was measured by a high-resolution time-of-flight aerosol mass spectrometer together with other online instruments. The average mass concentration of the submicron particles (PM1) was 5.7 ± 5.4 µg m−3 during the field campaign, ranging from 0.1 up to 33.3 µg m−3. Organic aerosol (OA) was the dominant component in PM1, with a fraction of 68 %. Three OA factors, i.e., biomass burning organic aerosol (BBOA), biomass-burning-influenced oxygenated organic aerosol (OOA-BB) and oxygenated organic aerosol (OOA), were resolved using positive matrix factorization analysis. The two oxygenated OA factors accounted for 87 % of the total OA mass. Three biomass burning events were identified by examining the enhancement of black carbon concentrations and the f60 (the ratio of the signal at mz 60 from the mass spectrum to the total signal of OA). Back trajectories of air masses and satellite fire map data were integrated to identify the biomass burning locations and pollutant transport. The western air masses from South Asia with active biomass burning activities transported large amounts of air pollutants, resulting in elevated organic concentrations up to 4-fold higher than those of the background conditions. This study at Mt. Yulong characterizes the tropospheric background aerosols of the Tibetan Plateau during pre-monsoon season and provides clear evidence that the southeastern edge of the Tibetan Plateau was affected by the transport of anthropogenic aerosols from South Asia.

Short summary
By monitoring aerosol properties as a function of high-resolution chemical composition, this study sheds light on the evolution processes of particles in the Tibetan Plateau background environment during the pre-monsoon season. A positive matrix factorization analysis integrated with a mesoscale meteorological model clearly shows that the southeastern edge of the Tibetan Plateau was affected by air pollutants transported from active biomass burning areas in South Asia.
Final-revised paper