A new oxygen mass-transfer model with an analytical solution was used to analyze the unsteady-state reaeration data of diffused aeration systems in order to find the volumetric mass-transfer coefficients that can be used to estimate the emission rate of volatile organic compounds from the same aeration systems. Two series of unsteady-state reaeration tests in 500-L and 4-L tanks were performed to validate the model. The air flow rate was varied from 2.25 x 10(-4) to 7.67 x 10(-4) normal m(3)/s in the 500-L tank and from 2.00 x 10(-5) to 8.67 x 10(-5) normal m(3)/s in the 4-L tank. The water temperature was varied from 288.5 to 294.1 K in the 500-L tank and from 299.5 to 304.3 K in the 4-L tank. Both the ASCE and the new oxygen mass-transfer models were used to analyze the unsteady-state reaeration data. An empirical equation was used to successfully correlate the volumetric mass-transfer coefficients.