The glowing wire represents a clean method of producing particles from a few nanometers to some tens of nanometers in diameter. An empirical rule is derived, identifying the materials, for which the method is applicable. A fraction of the particles is already charged at an efficiency comparable to radioactive chargers. This allows the direct use for mobility size classification and deposition without any further charging step. By applying a potential difference to the wire with respect to the housing, the charged particle yield can be increased by almost two orders of magnitude. Downstream of a mobility classifier a maximum concentration as high as 10(6) cm(-3) was reached. The generator shows excellent long-term stability. (c) 2006 Elsevier Ltd. All rights reserved.