Evaluation of techniques used in occupational airborne dust sampling

Includes bibliographical references (pages 39-40)Airborne dust evaluation of occupational environments is accomplished primarily by measurement of the mass concentration of dust in the air. Personal air sampling pumps are used for this purpose. The determination of the concentration of airborne dust is dependent on the volume of air drawn through the filter by the sampling pump and the mass of dust collected on the filter. Therefore, it is crucial that the flowrate and mass of dust be determined with a good degree of accuracy.\ud The relationship between dust-loading on the filter and decrease in flowrate is examined in this study. The effect of smaller particles of dust versus larger particles of dust in relation to flowrate variance is also examined. In addition, the variance of flowrate over time due to the dust loading is investigated. Finally, a new, possibly more accurate gravimetric analytical technique involving the weighing of the entire field monitor unit is compared with standard methods. It is concluded that the variation of flowrate due to dust loading under normal conditions is not significant, and the variation that does occur in the flowrate is primarily due to individual differences in the air sampling pumps. The new gravimetric technique indicated 2-5 percent greater mass of dust than the standard technique in comparative determinations for heavy dust loading on the filter