Risk Evaluation of Construction Workers' Exposure to Silica Dust and the Possible Lung Function Impairments

Aerosols generated during construction activities are an integral part of building operations. Considering the nature of materials used in construction activities, respirable dust contains crystalline silica and particulates not otherwise specified (PNOS). Due to lack of data regarding the occupational health status of Iranian construction workers, the objective of this study was to evaluate occupational exposure to silica and to examine their respiratory health status.

In this cross sectional study, 85 construction workers and 40 controls (without active exposure to construction dust) were studied. The workers' exposure to PNOS and silica aerosols was monitored by the NIOSH method No.0600 and a new Fourier transform infrared spectroscopy (FTIR)-based method, respectively. All subjects were also monitored for lung function parameters, such as forced expiratory volume/forced vital capacity (FEV₁/FVC), peak expiratory flow rate (PEFR), forced expiratory flow (FEF_25-75), FVC, and FEV₁.

The mean exposure of workers to respirable PNOS and silica was 9.8 (0.35) and 0.13 (0.019) mg/m³, respectively. The groups of construction workers showed significant differences in exposure to PNOS (P< 0.001) and silica (P= 0.007). The mean pulmonary function parameters, including FEV₁% and FVC%, were significantly lower among construction workers, compared to the control group (P< 0.001 and P= 0.009, respectively). The pulmonary status of 51.8% of construction workers showed moderate restriction, while 4.70% exhibited obstruction.

Considering the construction workers' excessive exposure to PNOS and silica, besides depressed lung function parameters, they can be classified as a high-risk group for respiratory diseases.