Classification and chemical compositions of individual particles at an eastern marginal site of Tibetan Plateau

Özet

Aerosol particles at Shangri-La, an eastern marginal site of Tibetan Plateau, were collected in July andAugust 2011. Morphologies and elemental compositions of individual particles were investigated throughtransmission electron microscopy coupled with energy dispersive X-ray spectroscopy. More than 14elements were detected in the aerosol particles, and S were detected in more than 70% of the 292analyzed particles. Six morphological types of individual particles were identified: soot, fly ash, complexsecondary particles, crustal minerals, organic particles, and metal particles. The aerosol particles mainlycomprised mineral particles (36.02%) and complex secondary particles (30.73%), followed by organicparticles (17.38%), soot (8.06%), fly ash (6.08%), and metal particles (1.01%). The diameters of fly ash, soot,and metal particles were less than 2 mm. Approximately 81% of the particles were internally or externallymixed with two or more aerosol components from different sources. Soot, fly ash, organic, and finemineral particles were commonly internally mixed with S-rich particles. Mineral particles tended tocommonly associate with visible coatings, probably formed through chemical reactions on the surface ofthe particles. Back-trajectories revealed that air mass arriving at Shangri-La were transported fromNortheast Burma, a region of the Indian subcontinent