Comparison of the column densities in 1 km s⁻¹ velocity bins for the program sources. Data for SgrB2-S are plotted in gray, G10.62-0.4 in red, G5.89-0.4 in blue and those toward B1730-130 and B1741-312 in green with error bars. The dotted lines show the mean relationships discussed in the text. The HF and p-H₂ O data have been obtained with Herschel (Sonnentrucker et al. 2015), the other data are from ALMA. The velocity range corresponding to the background sources are excluded. Only data points with S/N greater than 2.5σ, and with opacity lower than 3.5 are shown.