Fig. 8. Relationship between total ion current (IC) signal and volatile organic compound (VOC) flux from standard mixtures of VOC. The standard error (SE) for VOC flux was calculated by regression analysis from rate of VOC mass loss. Mean total IC signal and SE calculated from seven to eight total IC measurements. Fiber exposure time = 5 min; flow rate = 1 L min^–1 (16 cm s^–1); chamber temperature = 20°C.