Evaporation from a surface under atmospheric conditions can be difficult to characterize because the process involves both thermodynamics and kinetics. Thermogravimetric analysis was used to study the evaporation of D-limonene under several nitrogen flow rates above the surface. Instead of the common thermodynamic analysis, a kinetic treatment resulted in an activation energy of evaporation that is mostly composed of the enthalpy of vaporization with a smaller, additional energy due to the diffusion of molecules through the laminar boundary layer above the evaporating surface. As the flow rate over the sample increased from 60 to 200 mL/min, the activation energy decreased from 57.3 to 49.7 kJ mol −1 and approached reported enthalpy of vaporization values. Thus thermogravimetric analysis can be used to quantitatively characterize both the kinetic and thermodynamic aspects of nonequilibrium evaporation processes.