RESPIRABLE DUST DOSIMETER (RDD) FOR PERSONAL DUST EXPOSURE ASSESSMENT-A LABORATORY INVESTIGATION

The search for an improved or alternative instrument that will be able to measure occupational exposure more accurately and more reliably is continuing. Several developments have been taken place overseas with regard to real-time monitoring instruments for personal exposure assessment. In the light of these developments, the respirable dust dosimeter (RDD) described by Volkwein et al. (2000) appeared to be a promising development. RDD measures the dust exposure in differential pressure units (mm of Hg) indicating that it is a surrogate for the mass of dust on a gravimetric filter. This paper describes the results of an evaluation on theRDDunder laboratory conditions before evaluating them in underground mines for personal dust exposure assessment.The laboratory study has shown that there is a potential for the RDD sampler as a screening tool for engineering sample purposes. However, RDD was comparatively expensive during the research exercise costing approximately 16UK Pounds per RDD tube. Further, there was no well-accepted procedure on collect dust samples using RDD tube for further quartz analysis. Finally, due to its reasonable estimates of real-time cumulative shift dust exposure, and its small lightweight package, the RDD was further recommended for personal sampling purposes in the SouthAfrican mines