Scatter plots of various GMC properties as a function of the Hα luminosity for different environmental stellar surface densities measured at a scale of 500 pc, in a similar fashion to Fig. 4. Each column represents a bin of environmental stellar surface density, as defined in Sect. 6. From left to right: low density, average density, and high density environments. The red line shows the global correlation from Sect. 5 with a MOP of 40%.