Previous parameterizations of gas transfer velocity have attempted to cast this quantity as a function of wind speed or wind-stress. This study demonstrates that the presence of a surface film is effective at reducing the gas transfer velocity at constant wind-stress. Gas exchange experiments were performed at WHOI and UH using annular wind-wave tanks of different scales. Systematic variations of wind-stress and surfactant concentration (Triton-X-100) were explored to determine their influence on gas transfer velocity. Attempts to characterize the surface properties of the surfactant solutions were performed using mechanically generated capillary-wave packets. Results indicate a strong inverse relationship between gas transfer velocity and enhanced wave damping.