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

A balloon observation was carried out on 22 August in 1993 from Xianghe Scientific Balloon Base (39.75°N, 117.0°E) near Beijing in China. Individual aerosol particles in the five samples collected in the troposphere and lower stratosphere were analyzed by using a transmission electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer. Types of particles were classified by the quantitative EDX analysis and particle morphology. Following results were obtained by the analyses of aerosol particles in the radius range of 0.1–0.5 μm: (1) Sulfate particles were dominant (80%) in aerosol particles collected between 4 and 6 km altitude. (2) Sulfuric acid particles were present in 74% of particles at 8 km altitude, 91% at 11 km, 95% at 17 km and 88% at 21.2 km. (3) “S-rich” particles with K were collected both in the troposphere and lower stratosphere. It was considered that the particles containing K found at 5, 8 km altitude could originate from burning processes in the continent including the Tibetan plateau and be transported to the middle troposphere. (4) Sulfuric acid particles with Fe were present in 20–30% of sulfuric acid particles in the lower stratosphere. (5) Particles mainly composed of minerals were present in 6, 11% of particles at 5, 8 km, 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 in the troposphere. (7) Sea-salt particles with and without minerals were collected in the troposphere and lower stratosphere, suggesting the vertical transport by convective clouds.