The global budget of organic aerosol (OA) is poorly understood, and the processes that control formation and atmospheric transformation are not well constrained. Thus we rely on field measurements to provide information on the sources, distributions and processing of OA in the ambient atmosphere. In this talk I will highlight our recent efforts to use observations with models to investigate organic aerosol in diverse environments. This includes (1) investigating marine sources of OA (2) using satellite and aircraft observations to estimate the global budget of OA and (3) using satellite observations to investigate OA loading in the Southeastern US. I will highlight the complementary use of all scales of observations from surface in situ to satellite remote sensing to constrain this problem.