Airborne Dust Sampling And Analysis In Ornamental Stone Industry

Airborne dust produced during ornamental stone transformation process is considered one of the most risky factors for the health of workers employed in this industrial sector. The biggest health risk is due to the presence of free crystalline silica that can cause silicosis. The dry operations carried out manually by the workers during the stone finishing stage are the most dangerous for dust exposure risk. The common way to reduce dust at source in the stone conversion industry is the use of wet methods. When the control at source is not possible, dust transmission must be avoided using general or local exhaust ventilation. In manual operations this is normally achieved by working on an aspirating desk or inside an aspirating cabin. In order to find the best solution to reduce the amount of produced dust and to improve the air quality of working environment, a dust collection analysis campaign has been carried out in an ornamental stone conversion industry. Two types of ornamental stone hand working actions have been investigated (sawing and edge polishing). A big variety of ornamental stones have been selected for the tests (granites, limestones, sandstones, etc.). Dust personal samplers have been utilized for collection of both inhalable and respirable fractions. A sampling architecture involving both operator position and working areas topological assessment has been designed. Operating this way, a global overview of the dust distribution has been obtained. The results showed as the workers exposure to dust vary according to the different tools utilized and the different actions performed. A systematic comparison of the effects of edge polishing versus sawing demonstrated that, in spite of the apparently higher quantity of dust generated by sawing, the risk of dust inhalation for the workers is higher when polishing is performed. Furthermore the study demonstrated as common thoughts of the workers related to stone dustiness are not related with the associated risk for human respiratory system.