Popocatepetl ash charge as function of humidity and temperature

Here, we provide the absolute charge collected by volcanic ash (Popocatepetl) in the range of 250-500 microns through frictional interactions as a function of relative humidity (RH) and temperature. The range of RH is 0-50% (at 25 C) and the range of temperature is -20-40 C (at 30 % RH). Particles were charged triboelectrically and the charge was measuirend on individual particles using a miniature Farday cup. All values are reported in pico-Coulombs.