Particle Size Analysis of Cotton Dust Using Scanning Electron Microscopy

Particle size distributions of dusts generated in a model card room and collected on filter media by a vertical elutriator having a particle size cut-off of 15 μm dia have been determined using scanning electron microscopy. Photomicrographs, usually at 3000×, were made of the samples and the particle diameters were estimated by the Martin method. It was found that the average particle size of cotton dust samples measured by this technique was smaller than that reported in the literature obtained by light microscopy. It was also found that the distribution of particle sizes does not follow a simple log-normal distribution unless the smallest particles observed in this study are omitted. A bimodal or perhaps a multimodal distribution yields a better representation of the data. It is concluded that scanning electron microscopy is a practical and accurate method for sizing cotton dust particles on filter surfaces.