Observed [Ar/S] ratio (based on Ar I and S II) as a function of overall metallicity (top) and H I column density (bottom) in our sample of proximate systems. Blue circles correspond to the overall value in each system, and purple diamonds and red crosses show the H₂ and non-H₂ components, respectively. The dashed lines correspond to the corresponding mean values. The distribution is shown in the side panel. The green line corresponds to the mean [Ar/S] value (corrected to the same solar reference) and dispersion for intervening DLAs (Zafar et al. 2014b). Even though we tried to take blends into account, all points should be considered as upper limits in principle.