Observations of mean pollutant concentration profiles downwind of a block-sized model building are reported. These data are part of a more comprehensive field model study of building wake effects conducted in the U.S. Environmental Protection Agency's Fluid Modeling Facility. The study includes point measurements of pollutant concentration, velocity, turbulence, and full video images of smoke visualized plumes. The building orientation can have a significant effect on the maximum ground-level concentrations near a building. Slight angles were observed to result in the maximum being increased by a factor of 2-3 at x=3H. Concentrations were only increased by a factor of 1.5 at x=10H. The pattern of concentrations can be well explained by expected enhanced turbulence, vortex flow, and streamline convergence observed in previous studies.