Highly time-resolved in-situ measurements of airborne particles were made at Mt. Yulong (3410 m above sea level) on the southeastern edge of the Tibetan Plateau in China from 20 March to 14 April in 2015. Detailed chemical composition was measured by a high-resolution time-of-flight aerosol mass spectrometer together with other online instruments. Average mass concentration of the submicron particles (PM<sub>1</sub>) was 5.7 ± 5.4 μg m<sup>−3</sup> during the field campaign, ranging from 0.1 μg m<sup>−3</sup> up to 33.3 μg m<sup>−3</sup>. Organic aerosol (OA) was the dominant component in PM<sub>1</sub>, 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 <i>f</i><sub>60</sub> (the ratio of the signal at m/z 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 pollutants transport. The western air mass from Southeast Asia with active biomass burning activities transported large amount of air pollutants, resulting in elevated organic concentrations up to 4-fold higher than that of the background condition. 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 is affected by transport of anthropogenic aerosols from Southeast Asia.