Abstract :
Liquid and solid particles in the plumes of jet aircraft cruising in the upper troposphere and lower stratosphere lead to the formation of ice clouds (contrails), modify the microphysical properties of existing cirrus clouds, and provide sites for heterogeneous chemical reactions. Characterization of aviation-produced particles in terms of physico-chemical properties is an important step in assessing the global impact of aircraft emissions upon atmospheric chemistry and climate parameters. Chemistry and microphysics of the gas-aerosol system in aircraft plumes and its evolution in the atmosphere is a field of intense research. This paper reviews the current knowledge (mid-1998) and outlines possible atmospheric implications.