Accuracy of Real-Time Dust Monitors in Quarry Settings: A Pilot Field and Laboratory Evaluation

Accurate real-time dust monitoring methods are essential in workplaces where exposure to respirable crystalline silica (RCS) presents serious health risks. While real-time monitors are increasingly adopted due to their ability to quickly detect dust-generating activities, concerns remain regarding their accuracy compared to conventional gravimetric methods. This pilot study evaluated the performance of three real-time personal dust monitors: the SidePak™ AM520, Trolex XD1+, and Nanozen DustCount 9000, against a gravimetric reference in both field settings (South Australian quarries) and controlled laboratory environments. Pairwise comparisons of respirable dust (RD) concentrations were conducted across full work shifts. Geometric means from the real-time monitors were regressed against corresponding gravimetric measurements to derive correction coefficients, which were then used to estimate RCS exposure. Agreement between estimated and measured RCS values was assessed using Lin’s Concordance Correlation Coefficient (CCC). Field results revealed inconsistent accuracy for the SidePak™ and Nanozen monitors, with performance varying by task. For example, the SidePak™ overestimated RD by 51% for a truck driver but underestimated levels by up to 48% for other roles. The Trolex XD1+ consistently underestimated RD by 80–89%. All monitors underestimated dust levels under laboratory conditions. However, applying correction coefficients improved agreement with gravimetric data, yielding a high concordance for RCS estimates (Lin’s CCC = 0.89; 95% CI: 0.66–0.97). These findings highlight both the utility and limitations of real-time monitors. Site-specific calibration is essential to enhance their reliability, and further studies with larger datasets are recommended to refine correction factors and improve accuracy of real-time dust monitors.