Top: mass-size diagram for the ECC Hi-GAL objects based on the Hi-GAL Herschel column density maps. Sources with available distance estimates are shown. Red and black symbols indicate the clumps from Category I and II, respectively. Plus signs indicate the clumps in the outer part of the Galaxy and diamonds indicate the sources in the inner Galaxy. Green line indicates the mass-size threshold for massive star formation: m_lim = 870 M_⊙(r/ pc)^1.33 (Kauffmann & Pillai 2010). Solid lines show the ranges of masses and radii for sources with large distance discrepancies. Bottom: mass-size diagram based on the Hi-GAL column density maps. Masses and sizes are calculated within different column density limits; see details in text. Sources with peak column density values larger than 10²² cm^-2 are shown. Dashed lines indicate the sources in the outer Galaxy. Red lines indicate the sources without 70 μm point sources.