An electrostatic dust monitor

A smoke or dust particle carried by an air stream and subjected to high-voltage corona acquires a charge approximately proportional to its external surface area. If such ionized particles are precipitated at a collector electrode, the resultant flow of charge constitutes a current proportional to the rate of deposition of total dust surface, and a significant measure of the toxicity of a chimney discharge is obtained. The paper outlines the theory of a dust monitor incorporating this principle, describes some experiments in smoke measurement and examines the operation of prototype equipment in a pulverized-fuelfired boiler installation