Application of Cluster Analysis for Classification of Inhalation Exposure to Airborne Particles in a Tile and Ceramic Factory

Background: Particulate matter air pollution is one of the most important risk factors for cardiovascular and respiratory diseases. By increasing the number of mineral industries in the two past decades, workers in these industries are exposed to pathogenic respirable particulate matter pollutants. Cluster analysis is a multivariate statistical analysis method. Clustering creates groups or classes that the difference between the sub-groups samples is less than the difference between the groups. Therefore, this study assigns the cluster analysis to air sampling data collected from the various units of a tile factory. Methods: In this observational study, sampling from the respiratory zone of 93 workers in a tile and ceramic factory for both respirable and inhalable particles were performed. Sampling of inhalable particle based on NIOSH_0500 protocol and respirable particles based on NIOSH_0600 was conducted. Data were analyzed by both R 3.2.2 software and hierarchical cluster analysis with Ward link. Results: 92.47% of Workers were exposed to respirable particles less than TLV and 39.8% of them were exposed to inhalable particles more than TLV. The maximum average exposure for respirable particles 13.04 mg/m3 and inhalable particles 84.88 mg/m3 is respectively reported for crusher unit. The lowest average exposures to respirable (0.41 mg/m3) and inhalable (min=1.74 mg/m3) particles were observed in the glaze line division. Conclusion: Since the workers are exposed to concentrations more than the threshold limit value of respirable particles, and especially inhalable particles in some units, appropriate control measures must be considered to prevent possible consequences