A series of batch volatile organic compounds (VOC) emission tests were performed in a 500-L tank equipped with coarse-bubble diffusers at 0.82-3.29 m(3)/h diffused air flow rate and 289.2-305.6 K water temperature. The unsteady-state dissolved concentrations of p-xylene and tetrachloroethylene were measured during the tests and compared with the results predicted by both the American Society of Civil Engineers (ASCE)-based model and the two-zone model. The VOC emission rate decreased with increasing air flow rate and water temperature. The results also confirmed that the two-zone model could give a better prediction of the VOC emission rates while the ASCE-based model underestimated the VOC emission rates.