Log(Ar/O) as a function of 12+log(O/H) (left) and the ionisation degree, O²⁺/O (right), for the DESIRED-E H II regions (blue circles) or SFGs (black squares) having only Ar²⁺ (empty symbols) or Ar²⁺ and Ar³⁺ abundances (full symbols). Panels in the same row of the figure represent log(Ar/O) calculated using the ICF(Ar) scheme of Amayo et al. (2021, top panels), Izotov et al. (2006, middle panels) and Pérez-Montero et al. (2007, bottom panels). The dotted red line represents the mean value of log(Ar/O) obtained using each ICF(Ar). The orange diamonds indicate the mean log(Ar/O) values defined by all the points represented considering bins in 12+log(O/H) or O²⁺/O. The black dashed lines and the grey bands show the solar 12+log(O/H) and log(Ar/O) and their associated uncertainties, respectively, from Asplund et al. (2021).