Real-time measurements of atmospheric boundary layer structure and mixed layer height from ceilometer/lidar data can provide significant improvement to meteorological forecast models. In addition to determining the vertical mixing depth for which near surface contaminants may be dispersed in air quality and contaminant plume models, the distribution of aerosol within the boundary layer may provide additional information of the structure of the boundary layer including turbulent fluxes of heat, moisture, and chemical species. Several methods for objective detection of height of the mixed layer based on the maximum gradient, or the detection of the discontinuity of aerosol across the entrainment zone have been developed with promise for real-time applications. Utilizing the ceilometer installed at the DOE/Savannah River Site, we will evaluate the boundary layer determination methods. Significant aerosol backscatter sources such as wildfire and controlled burns, industrial emission plumes, and organic sources provide a useful data set for evaluating boundary layer flux measurements and model forecasts of mixed layer/planetary boundary layer height.