Carbon ionization equilibria with ionization and recombination from density-dependent metastable states, DR suppression and photoionization for quiet Sun at constant pressures p = 10¹⁴(full lines), 10¹⁵ (dot-dashed), and 10¹⁶ K cm⁻³ (dashed) shown for κ = 2, 5, 10, and Maxwellian distributions. The thin dotted lines correspond to the ionization equilibrium using the coronal approximation, that is, without level-resolved ionization, recombination, DR suppression, and photoionization.