Risk assessment of occupational and public exposures to airborne particulate matter arising from a subway construction site in Tehran, Iran

The objective of this study was to assess the health risk of occupational and public exposures to airborne particulate matter (PM) arising from a subway construction site in Tehran, Iran. The occupational exposure was determined by personal sampling in three occupational groups (drivers, workers, and engineers) and the environmental emission was estimated by sampling from five point exhausts. The PM was measured in terms of total suspended particles (TSP), particles with an aerodynamic diameter of less than 10 mu m (PM10), and less than 2.5 mu m (PM2.5). The ambient air concentrations of PM were modeled using AERMOD software and the health risk was estimated using AirQ+ software. The average (+/- standard deviation: SD) concentrations of TSP, PM10, and PM2.5 in the personal sampling were determined to be 3620 +/- 250, 1690 +/- 260, and 1350 +/- 140 mu g/m(3) for drivers, 2190 +/- 200, 1210 +/- 310, and 960 +/- 190 mu g/m(3) for workers, 690 +/- 70, 410 +/- 100, and 320 +/- 60 mu g/m(3) for engineers, respectively. The average PM2.5/PM10 ratio in the workplace and exhausts was as high as 0.79. The average increases in ambient air PM2.5 concentrations in the surrounding areas were predicted to be in the range of 2.4-23.8 mu g/m(3). The all-cause death rates (per 100,000 persons) attributable to PM2.5 from the construction project for the drivers, workers, engineers, and general people were estimated to be as high as 225, 214.5, 193, and 18, respectively. The results indicated that the health effects of the PM emission in the subway construction site were remarkable; therefore, more control measures for the workplace exposure and environmental emission should be considered.