One of the primary objectives of the preselected En-Vision M5 proposal is the monitoring of volcanogenic species in Venus’ atmosphere, one of the most prominent being sulphur dioxide (SO2). Monitoring SO2 below the clouds can be performed on the nightside near 2.4 μm, and is one science objective of the VenSpec-H channel (P.I.: A. C. Vandaele, BIRA) onboard EnVision. Monitoring SO2 above the clouds can be performed on the dayside in the 200-300nm range, and is the main science objective of the VenSpec-U channel (P.I.: E. Marcq, LATMOS). Here we present the analysis of two analogous datasets, namely IRTF/iSHELL ground based observations on the nightside of Venus, and the most recent reanalaysis of the Venus Express/SPICAV-UV dataset on the dayside of Venus.