Combined millimetre/sub-millimetre spectrum of foreground dust, synchrotron, anomalous microwave emission, etc., plotted with the band centres of the instruments on the Planck satellite denoted (grey vertical bands). The ALMA wide RF Band 2 (transparent dark blue region) will cover most of the Planck 70 and 100 GHz channels (Tauber et al. 2010), where the sum of the contributions is lowest. We also highlight Band 1 (35−50 GHz; transparent magenta region), which together with Wide RF Band 2 will likely leverage the free-free and spinning dust contributions. Figure is adapted from Dickinson et al. (2018) to highlight the role of the lower ALMA bands.