The measurement of electric charge on airborne dusts in textile industry workplaces

Airborne dusts become electrified during mechanical dispersal, and this may have a significant influence on their subsequent behavior. This paper presents an extensive series of measurements on the states of charge of airborne dusts at a range of jute, flax, cotton, glass, and asbestos textile industry workplaces. Distributions and magnitudes of charge carried by fine, inhalable particles of defined size were examined. The charges on clouds of dust particles were invariably distributed symmetrically between positive and negative. For each factory process producing dust consisting of predominantly isometric (i.e., nonfibrous) particles, the median charge on individual particles usually increased somewhat faster than linearly with particle diameter. The highest levels of charging appeared to be associated with the most energetic dust-making processes. From the industrial hygiene point of view, the levels of charge on the isometric inhalable dust particles associated with the jute, cotton, and glass textile factories were not thought high enough to influence dust uptake in the lungs of exposed workers. On the other hand, for the fibrous dusts associated with the asbestos factories, effective charging levels were high enough that the possibility of an effect on lung uptake caused by electrostatic image forces should not be neglected