Fig. 4From: Southern Hemisphere mid- and high-latitudinal AOD, CO, NO2, and HCHO: spatiotemporal patterns revealed by satellite observationsClimatological monthly mean distribution of the OMI formaldehyde (HCHO) tropospheric column (×1015 molecule cm−2) at 30–60° S. The color in each pixel reveals the median HCHO value for all available measurements from 2005 to 2016Back to article page