CO depletion versus the rotational temperature derived from NH₃. The green crosses represent sources in diffuse clouds, the blue triangles clumps in peaked clouds, and the red squares sources in multiply peaked clouds. The black dashed line marks the trend of an increase in CO depletion with colder temperatures for all the clumps, while the green, blue, and red solid lines mark the trends for the sources in diffuse, peaked, and multiply peaked clouds.