The appearance of carbon aerosol particles in the lower stratosphere

Very small carbonaceous particles, thought to be meteoritic, have been found in small quantities in the lower stratosphere during aircraft sampling flights. The sampling was accomplished using a quartz crystal microbalance (QCM) cascade impactor operating on a U-2 aircraft as it flew stratospheric sampling missions. Post flight analyses of the samples using scanning electron microscopy, X-ray energy spectroscopy and Auger electron spectroscopy have identified carbon particles 0.1 micron aerodynamic diameter and smaller in 16 of 28 sets of samples obtained between 1979 and 1983. The presence of such carbon particles in the stratosphere has implications relating to global climate, to the conversion of SO2 to sulfuric acid, and to the phenomenon of the Arctic haze.