Near field modelling of dust emissions caused by drilling and crushing

Abstract

This study compares modelling results to measured concentrations near dust sources in a natural stone quarry and in two aggregate quarries. In the natural stone quarry, the dust source was drilling and in the aggregate quarries, it was crushing. Aim is to evaluate performance of model BREEZE AERMOD under 200 m from the dust source, and to estimate AERMOD's applicability to represent short time dust dispersion events. If the model can capture the short-term variation of dust dispersion, it is usable in evaluation of weather conditions, when dust prevention should be enhanced, or production even paused, if there are critical objects near the quarry. The comparison between the measured and the modelled concentrations showed, that the model reacted more severely to changes in weather conditions, whereas the measurements showed no significant changes. AERMOD was not able to predict hourly concentration fluctuation, which is assumed to result from the lack of on-site meteorological data. The emission factors (EFs) determined for drilling either overestimated or underestimated the dust concentration. Therefore, the EF for drilling needs further research to obtain results reflecting the measured concentration levels better. The EF for crushing predicted well the dust dispersion near the dust source during the summer, but the model was unable to predict the dust concentration increase during the wintertime caused by the ground inversion, trapping the dust particles to remain near the ground. Modelling is applicable to aggregate quarries operating during unstable (non-inversion) meteorological conditions. Usage of on-site weather parameters is recommended.