A preliminary study on dust grains in the stratosphere

Abstract

Collected by means of a high-altitude scientific balloon and a self-made automatic sample collector, a total of 276 dust grains were selected for the study of shape, grain size and optical property. Some of the grains were examined by X-ray diffraction and electron microprobe techniques. The stratospheric dust grains can be classified as 6 types: cosmic dusts, cosmic dusts (?), microtektite, natural pollutants, artificial pollutants and the unknown substances. The different types of dust grains have different characters and distinguishing symbols. Widespread in the space of the solar system, cosmic dusts are the initial substances of the solar system and, to some degree, have recorded a great wealth of information on the early history of the solar system. So they have become one of the important objects in the field of cosmochemistry at present time. Since the 1960’s, scholars of many countries have collected cosmic dusts both in the space near the earth (using rockets, space probes and space shuttles)and in the stratosphere (using high-altitude balloons or U-2airplanes). According to the shape (the scanning electron microimage), element composition (the energy-dispersive X-ray spectrum) and optical properties of dust grains, the substances in the stratosphere can be classified as 5 types:cosmic dusts, alumina spheroids, terrestrial artificial pollutants, terrestrial natural pollutants and unknown substances (CDPET, 1982).