Raman lidar techniques have been developed to obtain the profiles of optical extinction at visible and ultraviolet wavelengths from airborne particulate matter, while at the same time providing profiles of water vapor, temperature and ozone. The variations in profiles of optical extinction provide an important way of describing the distribution of airborne particular matter during the evolution of air pollution events. Several sets of results from optical extinction, water vapor and ozone measurements obtained during the North East Oxidant and Particle Study (NARSTO-NE-OPS) program in Philadelphia PA during the summers of 1998, 1999 and 2001 provide the opportunity to investigate the physical processes associated with air pollution episodes. Additional measurements of atmosphere properties were obtained with other instruments at surface sites, on balloons and in aircraft. The measurements from the NE-OPS program have shown the importance of characterizing the vertical as well as the horizontal distribution of ozone and particulate matter during periods of increased air pollution. The present work focuses on efforts to improve our knowledge of aerosol optical properties because of the significance this topic assumes in the wake of studies that strongly correlate airborne particulate matter with adverse health effects. Model calculations are used to relate optical extinction measurements from particle sensors and those obtained using the Raman lidar.