Sampling Procedure
2.1 Apparatus
2.1.1 Samples are collected using a personal sampling pump, calibrated with the sampling device attached, to within ±5% of the recommended flow rate.
2.1.2 Samples are collected with 4-mm i.d. × 7-cm glass sampling tubes packed with two sections of coconut shell charcoal. The front section contains 110 mg and the back section contains 55 mg coconut shell charcoal. The sections are held in place with glass wool plugs. For this evaluation, tubes were purchased from SKC, Inc.