Journal of Knowledge & Health9420140921Evaluation of Local Exhaust Ventilation Efficiency to control emissions of Fe2O3 Dust in Ambient Air of the Oxide Screen Unit in steel industry45145110.1234/knh.v0i0.451FAMahdiJamshidi Rastani. fghorbani@umsha.ac.irFarshidGhorbani ShahnaAbdolrahmanBahramiSomayehHosseini20140118Introduction: There are numerous strategies to reduce of workers' exposure to chemical pollutants and control of emitted pollutants. Local exhaust ventilation (LEV) is most common equipment for engineering controls that is more preferred than other control methods. The aim of this study was to determine efficiency of LEV to control emissions dust in ambient air of a screen unit of steel industry.Methods: This is a descriptive study and in order evaluate efficiency of LEV, the screen unit divided into four parts including: ground floor, floor screen, hood 1 floor and platform hoods 15, 16, 17. The 36 air samples collected with the method of NIOSH -600 (cyclone samplers) were used to conduct both respirable and total dust sampling in the ON & OFF mode of ventilation system.Results: The results showed that the first floor had highest concentration with an average and range of 271.3 (118.1-434.47) mg/m3 (Approximately 18.2 times the PEL-OSHA) and its control efficiency was 3.9%. The lowest concentration was found at the screen floor with the average and range of 20.77 (8.95-31.51)mg/m3 (Approximately1.4 times the PEL-OSHA) and also its efficiency for ventilation in ''ON'' mode was 29.35 %. The average and range of concentration and overall efficiency in whole of the unit were found to be 127.6 (20.77-243.63) mg/m3 and 7.96 %, respectively. (TLV-ACGIH:10mg/m3, PEL-OSHA: 15mg/m3)Conclusion: In this study the efficiency of the system was different in different parts and LEV had not appropriate efficiency, which could be attributable to lack of regular and scheduled system for maintenance and monitoring of LEV and also change of production rates.