The talk focuses on airborne measurements of tropospheric mixing ratios and vertical profiles of formaldehyde, glyoxal, methylglyoxal (and higher carbonyls), and carbon monoxide over the Amazon Basin during the ACRIDICON-CHUVA campaign from the German High Altitude and Long-range research aircraft (HALO) in autumn 2014. Together with visible imagery and air mass back-trajectory modelling using NOAA HYSPLIT, we differenciate between the probing of background tropical air and measurements of moderately to strongly polluted air masses affected by biomass burning emissions or the city plume of Manaus. Further, for 12 near surface measurements of fresh biomass burning plumes, normalized excess mixing ratios of glyoxal and methylglyoxal with respect to formaldehyde are inferred and compared to recent studies.