Satellite-derived surface heat-flux maps are presented in order to illustrate the large horizontal variations in surface heating that can occur over heterogeneous terrain. Results of plume-model studies published by Lamb (1978) and Willis and Deardorff (1978) were modified to show that the ground-level pollutant concentrations depend closely upon the surface heat flux for the case of an elevated plume source during periods of free convection. We suggest that remotely determined surface heat-flux patterns can be used in making plume dispersion calculations.