Effects of transport on aerosols over the eastern slope of the Tibetan Plateau: synergistic contribution of Southeast Asia and the Sichuan Basin

Abstract

The aerosol optical properties and chemical components of PM2.1 (particulate matter with a diameter of 2.1 µm or less) were investigated at Mount Gongga on the eastern slope of the Tibetan Plateau from April 2012 to December 2014. The annual mean aerosol optical depth (AOD) was 0.35 ± 0.23, and the Ångström exponent was 1.0 ± 0.38. The AOD exhibited higher values in summer and winter, but lower values in spring and autumn. Dividing the observational periods into dry and wet seasons, the authors found that the concentrations of K+, elemental carbon, secondary inorganic aerosols, and primary and secondary organic carbon in the dry (wet) season were 0.29 (0.21), 0.88 (0.60), 7.4 (4.5), 7.5 (5.1), and 3.9 (12) µg m−3, respectively. Combined with trajectory analysis, the authors found that higher concentrations of K+, elemental carbon, and primary organic carbon indicated the effects of biomass burning from Southeast Asia during the dry season. However, the oxidation of volatile organic compounds was the main source of aerosols during the wet season, which originated from the Sichuan Basin.

Keywords

• Tibetan Plateau
• aerosol optical depth
• aerosol components
• biomass burning
• regional transport