For the first time, ultrafine volcanic aerosols are monitored continuously by Photoelectric Charging of Particles (PCP) at Mt. Etna, Sicily. The measured quantity, the photoelectric activity of the aerosols, ϵ, is a measure of the relative copper content in the nanometer sized particles and may be related to the release of chlorides from magma. A monitoring system was set up in the plume of Mt. Etna in 1991. The data show a connection to the volcanic activity. Events of magmatic activity on a short time scale of 45 sec as well as the general evolution over several months are apparent. ¿ American Geophysical Union 1992