Left panel: the ±1σ range of δ_GDR and α_CO derived from observed M_dust and using Eq. (10). Red region is from this work while the green region is from Aravena et al. (2016b). Our results generally agree with the SPT sources’ albeit having slightly larger α_CO or smaller δ_GDR. Right panel: the ratio between and M_dust of SMGs across the different redshifts. The SPT lensed SMGs in green points are from Aravena et al. (2016b), while our sources are in red. We also plot other SMGs from the literature in yellow filled squares (see references in text). The black line shows a best-fit to all the data points and dashed black lines show the ±1σ ranges (for the slope only) from the fit. The resulting relation is shown in the legend.