With the launch of the CALIPSO satellite into the A-Train, synergistic observations of aerosols from multiple sensors in the train are now possible. In early June and July, we started evaluating the combination of CALIPSO and the Ozone Monitoring Instrument (OMI) aerosol products. During the period from July 4-8, 2006, forest fire plumes from Alberta and the Yukon progressed across Canada and the US midwest, arriving in Maryland on July 8-9. OMI's aerosol index showed a plume which should have had a large aerosol optical depth, yet MODIS imagery from the same time showed less opacity. Lidar measurements from the Regional East Atmospheric Lidar Mesonet (REALM) site at the University of Maryland, Baltimore County, showed an elevated plume (~8-10km), which we interpreted as smoke. Combining these observations with the CALIPSO lidar data from the period makes a convincing case that the vertical information from these profiling sensors can aid in the retrieval of UV optical depths from OMI and explain these differences.