This study was carried out in order to raise workers'recognition of the effects of respirator use by providing concrete and practical data.

Twenty-six workers who dealt with toluene based ink and diluents at a gravure printing office in Seoul were investigated. The toluene exposure level and urinary hippuric acid level were monitored under respirator non-wearing(RNW) and under respiratory wearing(RW) conditions.

The mean concentrations of toluene exposed to each worker through the air of gravure printing office were 147.52+/-57.34 and 134.55+/-52.44 ppm on respirator non-wearing day and respirator wearing day, respectively. There was no significant difference in toluene exposure concentration for the two days. The mean concentration of urinary hippuric acid in RNW and RW groups were 1.51 (0.53) g/L and 0.49 (0.14) g/L, respectively, as measured at the end of the workday. There was a significant difference seen in urinary hippuric acid concentration between the two days. The urinary hippuric acid concentration began to increase at 4 hours after the start of the workday(13:00) in RNW. However, there was no significant increase until the end of the workday in the case of RW. The urinary hippuric acid concentration in RW reduced 89.3% as compared with the concentration seen in RNW. There was a significant correlation between the toluene concentration and the urinary hippuric acid concentration in RNW. The regression equation was Y (urinary hippuric acid concentration, g/L) = 0.007 X x(toluene concentration in the air, ppm) + 0.665.

Our results indicate that the respirator intercepted most toluene that may have been absorbed into the respiratory organs, and suggested that properly wearing a respiratory such as wearing the respirator during the entire workday and performing a proper fit test played an important role in the protection from toluene exposure.