The composition of individual aerosol particle in the troposphere and stratosphere over Xianghe (39.45 degrees N, 117.0 degrees E), China

A balloon observation was carried out on 22 August in 1993 from Xianghe Sci entific Balloon Base (39.75 degreesN, 117.0 degreesE) near Beijing in China . Individual aerosol particles in the five samples collected in the troposp here and lower stratosphere were analyzed by using a transmission electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer. Types o f particles were classified by the quantitative EDX analysis and particle m orphology. Following results were obtained by the analyses of aerosol parti cles in the radius range of 0.1-0.5 mum: (1) Sulfate particles were dominan t (80%) in aerosol particles collected between 4 and 6 km altitude. (2) Sul furic acid particles were present in 74% of particles at similar to 8 km al titude, 91% at 11 km, 95% at 17 km and 88% at 21.2 km. (3) "S-rich" particl es with K were collected both in the troposphere and lower stratosphere. It was considered that the particles containing K found at similar to 5, simi lar to 8 km altitude could originate from burning processes in the continen t including the Tibetan plateau and be transported to the middle tropospher e. (4) Sulfuric acid particles with Fe were present in 20-30% of sulfuric a cid particles in the lower stratosphere. (5) Particles mainly composed of m inerals were present in 6, 11% of particles at similar to 5, similar to 8 k m, indicating the vertical transport to the upper troposphere. (6) Mineral particles which contain sulfuric acid and sulfate suggest the formation of sulfuric acid and sulfate on mineral particles by heterogeneous processes i n the troposphere. (7) Sea-salt particles with and without minerals were co llected in the troposphere and lower stratosphere, suggesting the vertical transport by convective clouds. (C) 2001 Elsevier Science Ltd. All rights r eserved.