The passive badges were sent for analysis to the laboratory of the Bureau of Occupational and Environmental Diseases
of the Ministry of Health. Time Weight Average (TWA) was determined and used in statistical analysis. A gas chromatography machine was used for analysis. For the gas chromatography, a Column Aqua-Wax Polyethylene Glycol was used to analyze the toluene and xylene concentrations of the passive badges. Carbon disulfide was used for extraction.
The calibration and quality control was carried out by following the NIOSH method 1501 [25]. The standard threshold limit
value (TLV) of xylene in working environment by ACGIH is 100 ppm, and the standard TLV of ACGIH of
toluene is 20 ppm, respectively.