"BACKGROUND:Acute and chronic exposure to xylene can result in a range of negative health effects. However, xylene is widely used and emitted in the air of workplaces.OBJECTIVES:To evaluate xylene vapor concentrations to guide the design and evaluation of a local exhaust ventilation (LEV) system to reduce exposure in a pesticide production factory.METHOD:A real time volatile organic compound (VOC) monitor was used to determine the workers' time-weighted average (TWA) exposure. A LEV system was designed, and then, workers' exposure to xylene vapor was evaluated.RESULTS:We found that worker's exposure to xylene (4·7±5·5 ppm) was lower than the standards recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Occupational safety and health administration (OSHA). Despite the low TWA exposures, the short-term exposures for some workers were higher than STEL levels. Three canopy hoods were designed and installed with capture velocities of 0·508 m second(-1) and duct velocity of 10·16 m second(-1).CONCLUSION:We found that an exhaust ventilation system had a significantly reduced occupational exposure to xylene vapor."

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