MORPHOLOGICAL FEATURE AND CHEMICAL COM POSITION OF INDIVIDUAL PARTICLES IN THE TROPOSPHERE AND STRATOSPHERE

The collection of aerosol particles was carried out at Xianghe Scientific Balloon Observatory (39. 45°N, 117°E), Hebei province, China during Augusts and Septem bers of 1993 and 1994. The individual particles were collected on carbon-and Aluminium-coated films by a balloonborne impactor. A scanning electron microscope(SEM) equipped with an energy-dis-persive X-ray analyzer (EDXA) was applied to analyze the particles' morphologies and elemental compositions. The compounds of particles were examined with a laser microprobe mass spectrometer(LAMMS). Main results show as follows: (1) Irregular shape soil particles were frequently presented in the free troposphere. And in the stratosphere, the major particles had "satellite structure", which had been recognized as typical sulfuric acid droplet. Ammonium sulfate particles were of ten identified in the low-midtroposphere. (2) The elements of Si, Fe, Al and S were dominant constituents in particles. There were some" Si-rich" mineral particles even up to 20 km. (3) Not so many "Ca-rich" particles were shown during the experiment period. This implied that the particles came mainly from the locality, not from desert and loess areas. (4) The elements of Pand Niwere detected in particles. This is corresponding to the results of Beijing's particles collected near ground and Texas, American in 34～36 km, but the elements were not identified in Japan and American's particles collected in surface layer. (5) The compounds of individual particles contained mainly silicate, sulfate, nitrate and phosphate, and their changes with time and altitude were obvious. (6) It was found that the particles contained sulfate and nitrate or nitrate and phosphate meantime. It was difficult to comment this phenomenon. And the abundance values of nitrate, sulfate and silicate seemed bigger. (7) The chemical elements of particles were complex over Xianghe region.