We show that ubiquitous small conducting particles of meteoric origin in the mesosphere and stratosphere may explain some features of sprite occurrence and fine structure. The main processes involved are: electrostatic field amplification by microspires on the dust surface, cathode-like instability in their vicinity, autoemission and explosive emission of electrons. Additional observations, theoretical development and perhaps laboratory experiments are warranted. ¿ 2001 American Geophysical Union