Abstract
A surface-discharge microplasma device was used as a bipolar ion source for aerosol charging (Surface-discharge microplasma aerosol charger ; SMAC) . In this study, we developed and tested a practical version of the SMAC using a replaceable ring electrode. Characteristics of the SMAC as an aerosol charge neutralizer was investigated by a comparison with those of 241Am radioactive source. The equilibrium charge state could be obtained for polydisperse DOS and diesel exhaust aerosol with 10 to 200 nm in mobility diameters regardless of initial charge state. It is found that photoelectron is emitted from the surface of silver nanoparticles (<10 nm) when the particles suspended in nitrogen carrier gas are irradiated by ultraviolet light emitted from microplasma device, and it affects the unipolar charging of aerosol.
