Multi-axis differential optical absorption spectroscopy (MAX-DOAS) collects scattered sunlight spectra in a sequence of discrete viewing angles, and employs the DOAS method (inherently calibrated, and selective) to simultaneously retrieve multiple trace gases, e.g., nitrogen dioxide (NO2), nitrous acid (HONO), formaldehyde (HCHO), glyoxal (CHOCHO), bromine oxide (BrO), iodine oxide (IO), chlorine dioxide (OClO), water vapor (H2O), and oxygen dimers (O4, at 360nm, 477nm, and 632nm) slant column densities (SCD). Vertical profiles of these gases and multi-spectral aerosol extinction are inferred by combining experimentally constrained Monte-Carlo Radiative Transfer Modelling (RTM) and optimal estimation techniques to construct a model atmosphere that can in principle represent 3D clouds and aerosols. We present results from Atmospheric Chemistry field campaigns that deployed the innovative scanning CU Airborne and Ship MAX-DOAS instruments on several research aircraft (NOAA TwinOtter, NSF/NCAR GV) and cruises to study Air Quality in California, and probe halogen oxide radicals, and oxygenated hydrocarbons from the coastal to the oligotrophic tropical Pacific Ocean. Our observations identify the source of unaccounted glyoxal over oceans that has been measured from satellites, yet is currently not explained by global models. We further present the first detection of IO radicals and glyoxal in the tropical free troposphere downwind of deep convective storms.