Filter Preparation Techniques for Dust Exposure Determination by Gravimetric Analysis

Abstract Gravimetric analyses are frequently used to measure worker exposure to airborne particulate. In this study, two filter conditioning methods, designed to overcome moisture effects, were compared using two different filter media. Polyvinyl chloride (PVC) filters were used to sample wood dust and cork dust. Mixed cellulose ester (MCE) membrane filters were also used to sample cork dust. For each filter, pre- and postsampling weights were each determined twice: after conditioning for 48 hours in a silica gel dessicator and after being placed in an incubator set at 27°C and a nominal relative humidity of 50 percent. When MCE membrane filters were used, a statistically significant difference between conditioning methods was found in filter preweights. When PVC filters were used, weight differences between the two conditioning methods was found to be insignificant and considered potentially less important than differences due to material loss. Dessication of filters prior to weighing may result in incre...