This paper reports a study based on the application of conventions adopted by the American Conference of Governmental Industrial Hygienists (ACGIH), International Organization for Standardization (ISO) and Comité Europeén de Normalisation (CEN) for the classification of types of dust by particle size range. The occupational exposure characterization took into account the relations among dust concentrations at workplace, types of rocks worked on, wet and dry operations, machinery and tools used, and the size distribution of particles suspended in the air. The workplaces at the marble shops were characterized by high concentrations of dust in inhalable, thoracic and respirable fractions, produced by the tools used in the dry abrasive polishing sector. The silica concentrations were up to 16 times higher than the 0.05 mg/m³ occupational exposure limit recommended. The evaluation of a marble shop that made use of the wet abrasive polishing process showed that the probability of environmental concentrations exceeding the occupational reference values could be reduced by up to 99%.
marble shop; dust; silica; silicosis; occupational hygiene
