Prediction of Potential Dose Metrics for the Estimation of Health Effects due to Occupational Exposure in Samalut city, Egypt

Abstract

Potential dose metrics for the estimation of health effects including mass deposition fractions, mass deposition rates and mass deposition density rates were computed with a stochastic lung model based on the measured size distribution of elemental aerosols in the industrial area of Samalut in El-Minia (Egypt). Deposition was calculated for different physical activity levels; sitting, light and heavy exercise. The highest mass deposition fractions were observed in the extrathoracic region, while deposition in bronchial and acinar regions was consistently smaller irrespective of the chemical species. This difference between extrathoracic and lung regions was further exacerbated in the case of mass deposition density rates due to significant differences in related surface areas. Mass deposition fractions and mass deposition rates increased with airway generation number, reaching a maximum in the acinar region, while mass deposition density rates dropped significantly from the maximum in the large bronchi to the distal acinar airways. Mass deposition rates and deposition density rates increase with physical activity and thus are highest for heavy exercise breathing conditions. Mass deposition density rates suggest that the bronchial region is the primary target for health effects of inhaled particles.