An Electrical Method for Investigating the Nature and Behavior of Small, Airborne, Charged Particles

A theoretical and experimental analysis of the current-voltage (dc) characteristic of a parallel-plate condenser through which the small, airborne, charged particles of an aerosol are passed continuously shows that a charge-weighted distribution of radius (or radius squared)-charge ratio may be obtained when certain experimental conditions are satisfied. Examination of such a distribution for an aerosol (particles less than a micron in diameter) before and after passage through a small (20-liter) settling chamber shows that the classes of particles in the distribution that are easiest to collect in the condenser are also the classes that disappear most rapidly in the chamber. It is pointed out that the methods employed would become less tedious and more powerful when used with a dispersion of constant-size particles, and that they are well adapted for certain fundamental investigations of aerosol properties.